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# Investigating The Lever V1 6 Formatted

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### Investigating The Lever V1 6 Formatted

1. 1. ITEM #1 Examine the student task at the end of the lever investigation, which uses information from the lever investigation below to create a procedure for a pulley. Investigating the Lever and Pulley A lever is another example of a simple machine. It can make lifting something much easier. In this demonstration you will learn how the lever works. Your teacher will show how you can use a lever when you work to lift a can or similar object. Set-up: The diagram below shows the set-up for this investigation. In this investigation, the goal is to lift the block straight up, as shown in the two diagrams below. QuickTimeª and a TIFF (Uncompressed) decompressor are needed to see this picture. A similar investigation will also be lifting the block to the same height using various levers. The first lever will have the fulcrum located in the center of the board. For the next two setups, you will move the fulcrum closer and closer to the block. You will compare the force and distance in these situations. Materials: List the materials you will need to do this investigation.
2. 2. Procedure Part 1: Lifting the block 1. Prepare the first setup by tying a string around the block. 2. Lift the block to a height of 10 cm with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 3. Lift the block again to the top of the stack of books, and measure the distance (in centimeters) that the person’s hand moves while lifting the block. Record this measurement in your data table. Repeat this procedure three times to get three sets of measurements. Part 2: Using the lever to lift the block 1. Attach the clamp to the ring stand near the top. Use the other half of the clamp to attach the bolt. The bolt will be the fulcrum of your lever. 2. Slide the wooden lever onto the bolt, so that the bolt goes through the middle of the lever. Secure the lever by screwing on the wing nut (not too tight). 3. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where the block is now hanging. 4. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 5. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while pulling down on the lever. Repeat this procedure three times to get three sets of measurements. Part 3: Using the lever to lift the block (fulcrum closer to block) 1. Move the fulcrum (where the lever is attached to the bolt) to one of the holes closer to the block. 2. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where the block is now hanging. 3. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 4. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while pulling down on the lever. Repeat this procedure three times to get three sets of measurements. Part 3: Using the lever to lift the block (fulcrum even closer to block) 1. Move the fulcrum even closer to the block. 2. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where the block is now hanging. 3. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 4. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while pulling down on the lever. Repeat this procedure three times to get three sets of measurements.
3. 3. Data: The following tables are for use in collecting data from the investigation. Without Lever With Lever (fulcrum at center) Force (N) Distance (cm) Force (N) Distance (cm) Trial 1 Trial 1 Trial 2 Trial 2 Trial 3 Trial 3 Total Total Average Average With Lever (fulcrum closer to With Lever (fulcrum very close to block) block) Force (N) Distance (cm) Force (N) Distance (cm) Trial 1 Trial 1 Trial 2 Trial 2 Trial 3 Trial 3 Total Total Average Average Graphs: Using the averages from the data, the results for the force and distance measurements can be graphed below. QuickTimeª and a TIFF (Uncompressed) decompressor are needed to see this picture.
4. 4. QuickTimeª and a TIFF (Uncompressed) decompressor are needed to see this picture.
5. 5. Results (What does your data say?) Conclusions (What can you conclude about levers in general?) Evidence (What does your graph show to support your conclusion?) Was your hypothesis supported? Was it complete? Student Task: Using the diagram and information for the pulley shown below, create a similar procedure and hypothesis to investigate the effect on force and distance using a pulley. Investigating the Pulley A pulley is another example of a simple machine. It can make lifting something much easier. In this investigation you will learn how pulleys work. You might want to use pulleys when you work on the design challenge and build a machine to lift a can.
6. 6. ITEM #2 Examine the lever investigation, and graph the data collected to answer the questions. Investigating the Lever and Pulley A lever is another example of a simple machine. It can make lifting something much easier. In this investigation you will learn how the lever works. You might want to use a lever when you work on the design challenge and build a machine to lift a can. In this investigation you will answer the question: How do different levers help you lift an object? Hypothesis: The greater the distance of the fulcrum from the brick, the less force that needs to be applied to the lever. Set-up: The diagram below shows the set-up for this investigation. You will be lifting the block straight up and you will also be lifting the block to the same height using various levers. The first lever will have the fulcrum located in the center of the board. For the next two setups, you will move the fulcrum closer and closer to the block. You will compare the force and distance in these situations. Your teacher will provide you with the materials to conduct the investigation. QuickTimeª and a TIFF (Uncompressed) decompressor are needed to see this picture.
7. 7. Procedure Part 1: Lifting the block 1. Prepare the first setup by tying a string around the block. 2. Lift the block to a height of 10 cm with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 3. Lift the block again to the top of the stack of books, and measure the distance (in centimeters) that the person’s hand moves while lifting the block. Record this measurement in your data table. Repeat this procedure three times to get three sets of measurements. Part 2: Using the lever to lift the block 1. Attach the clamp to the ring stand near the top. Use the other half of the clamp to attach the bolt. The bolt will be the fulcrum of your lever. 2. Slide the wooden lever onto the bolt, so that the bolt goes through the middle of the lever. Secure the lever by screwing on the wing nut (not too tight). 3. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where the block is now hanging. 4. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 5. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while pulling down on the lever. Repeat this procedure three times to get three sets of measurements. Part 3: Using the lever to lift the block (fulcrum closer to block) 1. Move the fulcrum (where the lever is attached to the bolt) to one of the holes closer to the block. 2. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where the block is now hanging. 3. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 4. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while pulling down on the lever. Repeat this procedure three times to get three sets of measurements. Part 4: Using the lever to lift the block (fulcrum even closer to block) 1. Move the fulcrum even closer to the block. 2. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where the block is now hanging. 3. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 4. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while pulling down on the lever. Repeat this procedure three times to get three sets of measurements.
8. 8. Data: Below is the data collected by a student doing this investigation. Without Lever With Lever (fulcrum at center) Force (N) Distance (cm) Force (N) Distance (cm) Trial 1 23 18 Trial 1 23 18 Trial 2 22 18 Trial 2 22 18 Trial 3 23 18 Trial 3 23 18 Total Total Average Average With Lever (fulcrum closer to With Lever (fulcrum very close to block) block) Force (N) Distance (cm) Force (N) Distance (cm) Trial 1 17 22 Trial 1 11 24 Trial 2 18 21 Trial 2 10 26 Trial 3 17 24 Trial 3 8 26 Total Total Average Average Use this data to construct the graphs shown below. QuickTimeª and a TIFF (Uncompressed) decompressor are needed to see this picture.
9. 9. QuickTimeª and a TIFF (Uncompressed) decompressor are needed to see this picture. Was your hypothesis supported? Was it complete?
10. 10. ITEM #3 Examine the lever investigation, and graph the data collected to answer the questions. Investigating the Lever and Pulley A lever is another example of a simple machine. It can make lifting something much easier. In this investigation you will learn how the lever works. You might want to use a lever when you work on the design challenge and build a machine to lift a can. How do different levers help you lift an object? Levers are used to reduce the amount of force that is required to lift an object, or to change the direction of the force required to lift an object. For instance, if you lift up an object without using a lever, and then try to lift the object with a lever, as shown in the first diagram below, the force required to pull on the object is the same, but the direction you pull changes (pulling down instead of pulling up on the object directly). If you move the fulcrum of the object so that it is closer to the brick, the distance you pull will be greater, but the amount of force will be less. This is because the amount of force and distance you move that force can be multiplied to get the amount of work done. In other words: W=Fxd (W = Work, F = force in Newtons, d = distance in cm) Set-up: The diagram below shows the set-up for this investigation. You will be lifting the block straight up and you will also be lifting the block to the same height using various levers. The first lever will have the fulcrum located in the center of the board. For the next two setups, you will move the fulcrum closer and closer to the block. You will compare the force and distance in these situations. Your teacher will provide you with the materials to conduct the investigation. QuickTimeª and a TIFF (Uncompressed) decompressor are needed to see this picture.
11. 11. USING THE PROCEDURE BELOW, STATE WHETHER THE DATA GATHERED BY THE STUDENT IS ACCURATE AND FITS THE EQUATION FOR WORK. Procedure Part 1: Lifting the block 1. Prepare the first setup by tying a string around the block. 2. Lift the block to a height of 10 cm with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 3. Lift the block again to the top of the stack of books, and measure the distance (in centimeters) that the person’s hand moves while lifting the block. Record this measurement in your data table. Repeat this procedure three times to get three sets of measurements. Part 2: Using the lever to lift the block 1. Attach the clamp to the ring stand near the top. Use the other half of the clamp to attach the bolt. The bolt will be the fulcrum of your lever. 2. Slide the wooden lever onto the bolt, so that the bolt goes through the middle of the lever. Secure the lever by screwing on the wing nut (not too tight). 3. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where the block is now hanging. 4. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 5. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while pulling down on the lever. Repeat this procedure three times to get three sets of measurements. Part 3: Using the lever to lift the block (fulcrum closer to block) 1. Move the fulcrum (where the lever is attached to the bolt) to one of the holes closer to the block. 2. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where the block is now hanging. 3. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 4. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while pulling down on the lever. Repeat this procedure three times to get three sets of measurements. Part 4: Using the lever to lift the block (fulcrum even closer to block) 1. Move the fulcrum even closer to the block. 2. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where the block is now hanging. 3. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 4. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while pulling down on the lever. Repeat this procedure three times to get three sets of measurements.
12. 12. Data: Below is the data collected by a student doing this investigation. Without Lever With Lever (fulcrum at center) Force (N) Distance (cm) Force (N) Distance (cm) Trial 1 23 18 Trial 1 23 18 Trial 2 22 18 Trial 2 22 18 Trial 3 23 18 Trial 3 23 18 Total Total Average Average With Lever (fulcrum closer to With Lever (fulcrum very close to block) block) Force (N) Distance (cm) Force (N) Distance (cm) Trial 1 17 22 Trial 1 11 24 Trial 2 18 21 Trial 2 10 26 Trial 3 17 24 Trial 3 8 26 Total Total Average Average Use this data to determine if the data was collected correctly by using the formula for work. Show your work.
13. 13. ITEM #4 Examine the student task at the end of the lever investigation, which uses information from the lever investigation below to create a procedure for a pulley. Investigating the Lever and Pulley A lever is another example of a simple machine. It can make lifting something much easier. In this demonstration you will learn how the lever works. Your teacher will show how you can use a lever when you work to lift a can or similar object. Set-up: The diagram below shows the set-up for this investigation. In this investigation, the goal is to lift the block straight up, as shown in the two diagrams below. QuickTimeª and a TIFF (Uncompressed) decompressor are needed to see this picture. A similar investigation will also be lifting the block to the same height using various levers. The first lever will have the fulcrum located in the center of the board. For the next two setups, you will move the fulcrum closer and closer to the block. You will compare the force and distance in these situations. Materials: List the materials you will need to do this investigation.
14. 14. Procedure Part 1: Lifting the block 1. Prepare the first setup by tying a string around the block. 2. Lift the block to a height of 10 cm with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 3. Lift the block again to the top of the stack of books, and measure the distance (in centimeters) that the person’s hand moves while lifting the block. Record this measurement in your data table. Repeat this procedure three times to get three sets of measurements. Part 2: Using the lever to lift the block 1. Attach the clamp to the ring stand near the top. Use the other half of the clamp to attach the bolt. The bolt will be the fulcrum of your lever. 2. Slide the wooden lever onto the bolt, so that the bolt goes through the middle of the lever. Secure the lever by screwing on the wing nut (not too tight). 3. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where the block is now hanging. 4. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 5. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while pulling down on the lever. Repeat this procedure three times to get three sets of measurements. Part 3: Using the lever to lift the block (fulcrum closer to block) 1. Move the fulcrum (where the lever is attached to the bolt) to one of the holes closer to the block. 2. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where the block is now hanging. 3. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 4. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while pulling down on the lever. Repeat this procedure three times to get three sets of measurements. Part 3: Using the lever to lift the block (fulcrum even closer to block) 1. Move the fulcrum even closer to the block. 2. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where the block is now hanging. 3. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 4. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while pulling down on the lever. Repeat this procedure three times to get three sets of measurements.
15. 15. Data: The following tables are for use in collecting data from the investigation. Without Lever With Lever (fulcrum at center) Force (N) Distance (cm) Force (N) Distance (cm) Trial 1 23 18 Trial 1 -23 -18 Trial 2 22 18 Trial 2 -22 -18 Trial 3 23 18 Trial 3 -23 -18 Total Total Average Average With Lever (fulcrum closer to With Lever (fulcrum very close to block) block) Force (N) Distance (cm) Force (N) Distance (cm) Trial 1 -17 -22 Trial 1 -11 -24 Trial 2 -18 -21 Trial 2 -10 -26 Trial 3 -17 -24 Trial 3 -8 -26 Total Total Average Average Fill in the blank in the statement below: As the amount of force to move an object is reduced, the amount of distance the lever is moved __________because… Using a Pulley: Create a hypothesis and similar procedure to investigate the effect on force and distance using a pulley instead of a lever. Show diagrams for each step of the procedure.
16. 16. ITEM #5 Examine the lever investigation, and graph the data collected to answer the questions. Investigating the Lever and Pulley A lever is another example of a simple machine. It can make lifting something much easier. In this investigation you will learn how the lever works. You might want to use a lever when you work on the design challenge and build a machine to lift a can. In this investigation you will answer the question: How do different levers help you lift an object? Hypothesis: The greater the distance of the fulcrum from the brick, the less force that needs to be applied to the lever. Set-up: The diagram below shows the set-up for this investigation. You will be lifting the block straight up and you will also be lifting the block to the same height using various levers. The first lever will have the fulcrum located in the center of the board. For the next two setups, you will move the fulcrum closer and closer to the block. You will compare the force and distance in these situations. Your teacher will provide you with the materials to conduct the investigation. QuickTimeª and a TIFF (Uncompressed) decompressor are needed to see this picture.
17. 17. Procedure Part 1: Lifting the block 1. Prepare the first setup by tying a string around the block. 2. Lift the block to a height of 10 cm with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 3. Lift the block again to the top of the stack of books, and measure the distance (in centimeters) that the person’s hand moves while lifting the block. Record this measurement in your data table. Repeat this procedure three times to get three sets of measurements. Part 2: Using the lever to lift the block 1. Attach the clamp to the ring stand near the top. Use the other half of the clamp to attach the bolt. The bolt will be the fulcrum of your lever. 2. Slide the wooden lever onto the bolt, so that the bolt goes through the middle of the lever. Secure the lever by screwing on the wing nut (not too tight). 3. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where the block is now hanging. 4. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 5. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while pulling down on the lever. Repeat this procedure three times to get three sets of measurements. Part 3: Using the lever to lift the block (fulcrum closer to block) 1. Move the fulcrum (where the lever is attached to the bolt) to one of the holes closer to the block. 2. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where the block is now hanging. 3. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 4. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while pulling down on the lever. Repeat this procedure three times to get three sets of measurements. Part 4: Using the lever to lift the block (fulcrum even closer to block) 1. Move the fulcrum even closer to the block. 2. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where the block is now hanging. 3. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 4. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while pulling down on the lever. Repeat this procedure three times to get three sets of measurements.
18. 18. Data: Below is the data collected by a student doing this investigation. Without Lever With Lever (fulcrum at center) Force (N) Distance (cm) Force (N) Distance (cm) Trial 1 23 18 Trial 1 23 18 Trial 2 22 18 Trial 2 22 18 Trial 3 23 18 Trial 3 23 18 Total Total Average Average With Lever (fulcrum closer to With Lever (fulcrum very close to block) block) Force (N) Distance (cm) Force (N) Distance (cm) Trial 1 17 22 Trial 1 11 24 Trial 2 18 21 Trial 2 10 26 Trial 3 17 24 Trial 3 8 26 Total Total Average Average Use this data to construct the graphs shown below. QuickTimeª and a TIFF (Uncompressed) decompressor are needed to see this picture.
19. 19. QuickTimeª and a TIFF (Uncompressed) decompressor are needed to see this picture.
20. 20. Data: Below is the data collected by a second student doing this investigation with different equipment. Without Lever With Lever (fulcrum at center) Force (N) Distance (cm) Force (N) Distance (cm) Trial 1 35 21 Trial 1 36 21 Trial 2 35 21 Trial 2 34 21 Trial 3 33 21 Trial 3 34 20 Total Total Average Average With Lever (fulcrum closer to With Lever (fulcrum very close to block) block) Force (N) Distance (cm) Force (N) Distance (cm) Trial 1 27 24 Trial 1 21 35 Trial 2 25 25 Trial 2 20 37 Trial 3 25 25 Trial 3 18 37 Total Total Average Average Use this data to construct the graphs shown below. QuickTimeª and a TIFF (Uncompressed) decompressor are needed to see this picture.
21. 21. QuickTimeª and a TIFF (Uncompressed) decompressor are needed to see this picture.
22. 22. Using the data from the two students, what can you conclude about the relationship between force and distance? What evidence do you have for your conclusion? What similarities or differences do you see in the graphs for the two students? What might account for these? Explain the general relationship between force
23. 23. ITEM #6 Investigating the Lever and Pulley A lever is another example of a simple machine. It can make lifting something much easier. In this investigation you will learn how the lever works. You might want to use a lever when you work on the design challenge and build a machine to lift a can. Investigating the Lever and Pulley A lever is another example of a simple machine. It can make lifting something much easier. In this investigation you will learn how the lever works. You might want to use a lever to lift a can. How do different levers help you lift an object? Levers are used to reduce the amount of force that is required to lift an object, or to change the direction of the force required to lift an object. For instance, if you lift up an object without using a lever, and then try to lift the object with a lever, as shown in the first diagram below, the force required to pull on the object is the same, but the direction you pull changes (pulling down instead of pulling up on the object directly). If you move the fulcrum of the object so that it is closer to the brick, the distance you pull will be greater, but the amount of force will be less. Set-up: The diagram below shows the set-up for this investigation. In this investigation, the goal is to lift the block straight up, as shown in the two diagrams below. A similar investigation will also be lifting the block to the same height using various levers. The first lever will have the fulcrum located in the center of the board. For the next two setups, you will move the fulcrum closer and closer to the block. You will compare the force and distance in these situations. QuickTimeª and a TIFF (Uncompressed) decompressor are needed to see this picture. Materials: List the materials you will need to do this investigation.
24. 24. Procedure Part 1: Lifting the block 1. Prepare the first setup by tying a string around the block. 2. Lift the block to a height of 10 cm with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 3. Lift the block again to the top of the stack of books, and measure the distance (in centimeters) that the person’s hand moves while lifting the block. Record this measurement in your data table. Repeat this procedure three times to get three sets of measurements. Part 2: Using the lever to lift the block 1. Attach the clamp to the ring stand near the top. Use the other half of the clamp to attach the bolt. The bolt will be the fulcrum of your lever. 2. Slide the wooden lever onto the bolt, so that the bolt goes through the middle of the lever. Secure the lever by screwing on the wing nut (not too tight). 3. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where the block is now hanging. 4. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 5. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while pulling down on the lever. Repeat this procedure three times to get three sets of measurements. Part 3: Using the lever to lift the block (fulcrum closer to block) 1. Move the fulcrum (where the lever is attached to the bolt) to one of the holes closer to the block. 2. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where the block is now hanging. 3. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 4. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while pulling down on the lever. Repeat this procedure three times to get three sets of measurements. Part 3: Using the lever to lift the block (fulcrum even closer to block) 1. Move the fulcrum even closer to the block. 2. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where the block is now hanging. 3. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 4. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while pulling down on the lever. Repeat this procedure three times to get three sets of measurements.
25. 25. Data: The following tables are for use in collecting data from the investigation. Without Lever With Lever (fulcrum at center) Force (N) Distance (cm) Force (N) Distance (cm) Trial 1 23 18 Trial 1 -23 -18 Trial 2 22 18 Trial 2 -22 -18 Trial 3 23 18 Trial 3 -23 -18 Total Total Average Average With Lever (fulcrum closer to With Lever (fulcrum very close to block) block) Force (N) Distance (cm) Force (N) Distance (cm) Trial 1 -17 -22 Trial 1 -11 -24 Trial 2 -18 -21 Trial 2 -10 -26 Trial 3 -17 -24 Trial 3 -8 -26 Total Total Average Average Graphs: Using the averages from your data, graph the results for the force below. Be sure to label the vertical axis on each graph with the appropriate units. QuickTimeª and a TIFF (Uncompressed) decompressor are needed to see this picture.
26. 26. Investigating Pulleys A pulley is another example of a simple machine. It can make lifting something much easier. In this investigation you will learn how pulleys work. You might want to use pulleys when you work on the design challenge and build a machine to lift a can. USE THE FOLLOWING EXPERIMENTAL PROCEDURE TO CONDUCT AN INVESTIGATION OF THE FORCE AND DISTANCE USED TO MOVE A CAN USING A PULLEY AND COMPLETE THE RELATED TABLES AND GRAPHS. Set-up: The diagram below shows the set-up for this investigation. You will be lifting the block straight up and you will also be lifting the block using a variety of pulley arrangements. The first pulley arrangement is a fixed pulley. The second is a free pulley and the third combines a fixed and a free pulley. You will compare the force and distance in these situations. Materials: List the materials you will need to do this investigation.
27. 27. Procedure Part 1: Lifting the block 1. Prepare the first setup by tying a string around the block. 2. Lift the block to a height of 20 cm using the spring scale, and measure the amount of force (in newtons) you apply. Record this measurement in your data table. 3. Lift the block again to a height of 20 cm, and measure the distance (in centimeters) that the person’s hand moves while lifting the block. Record this measurement in your data table. Repeat this procedure three times to get three sets of measurements. Part 2: Using a fixed pulley to lift the block 1. Set up the fixed pulley. (See diagram above.) Attach the pulley to the top of the ring stand and tie one end of the string to the block. Thread the string through the pulley so that as you pull down on the free end, the block moves up. Set the ruler near the block to use as a reference height. Attach the spring scale to the free end of the string. 2. Lift the block to a height of 20cm by pulling on the string with the spring scale. You can pull at any angle. Measure the amount of force (in newtons) you apply. Record this measurement in your data table. 3. Lift the block again to 20 cm, and measure the distance (in centimeters) that the person’s hand moves. Record this measurement in your data table. Repeat this procedure three times to get three sets of measurements. Part 3: Using a free pulley to lift the block 1. Set up the free pulley. (See the diagram above.) Tie a piece of string to the ring stand. Thread the free end of the string through the pulley. Tie the block to the pulley so that as you pull up on the string the pulley (with the block attached) moves up. Set the stack of books near the block to use as a reference height. Attach the spring scale to the free end of the string. 2. Lift the block to a height of 20 cm by pulling on the string with the spring scale. You can pull at any angle. Measure the amount of force (in newtons) you apply. Record this measurement in your data table. 3. Lift the block again to 20 cm, and measure the distance (in centimeters) that the person’s hand moves. Record this measurement in your data table. Repeat this procedure three times to get three sets of measurements. Part 4: Using a fixed and a free pulley to lift the block 1. Set up the fixed and free pulleys. (See the diagram above.) Use the free pulley setup from the previous part. Instead of pulling on the free end of the string, attach a second pulley to the ring stand (like the fixed pulley in the first part) and thread the free end of the string through this pulley. Set the stack of books near the block to use as a reference height. Attach the spring scale to the free end of the string. 2. Lift the block to a height of 20 cm by pulling on the string with the spring scale. You can pullat any angle. Measure the amount of force (in newtons) you apply. Record this measurement in your data table. 3. Lift the block again to 20 cm, and measure the distance (in centimeters) that the person’s hand moves. Record this measurement in your data table. Repeat this procedure three times to get three sets of measurements.
28. 28. Data: Without Pulley With Fixed Pulley Force (N) Distance (cm) Force (N) Distance (cm) Trial 1 Trial 1 Trial 2 Trial 2 Trial 3 Trial 3 Total Total Average Average With Free Pulley With Fixed and Free Pulleys Force (N) Distance (cm) Force (N) Distance (cm) Trial 1 Trial 1 Trial 2 Trial 2 Trial 3 Trial 3 Total Total Average Average Graphs: Using the averages from your data, graph the results for the force below. Be sure to label the vertical axis on each graph with the appropriate units. What can you conclude about the amount of force required to move an object using a lever? QuickTimeª and a What can you conclude about the amount of TIFF (Uncompressed) decompressor are needed to see this picture. force required to move an object using pulleys? What can you conclude about the similarities between the lever and pulley?