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SCIENCE NINE QUARTER FOUR WEEK ONE.pptx
- 19. Speedometer indicates thespeed of a vehicle. It is usually combined with a device known as odometer that records the distance travel.
- 40. Gravity is anatural force that causes objects to fall towards the earth hence, the acceleration due to gravity is always directed downwards.
- 41. Projectile motion isa form of motion where an objects moves in a curve path.
Editor's Notes
- #3 In grade 8 you have learned the 2nd law of newton which is the law of motion
- #4 Read.
- #5 According to this law the net force is equal to the product of the mass of the object in each acceleration. Lets have a short revirew before we proceed to our topic and to refresh your mind.
- #12 Always remember read. Usually the acceleration of the body may change or vary from time to time due to the several factor. In that case when can we say that there is a constant accdeleration?
- #13 Lets have a review about uniformly accelerated motion
- #14 Are you familiar with this blue uniform men while usually position in the busy streets.who are they and what do they do?
- #15 They play a crucial role in maintaining the flow of traffic and implementing laws and rules and regulations on the road that every motorist should follow.
- #16 They can also be considered as frontliners.
- #17 Speed limits are observed on roads. They vary and depends on several conditions. Speed limits for high ways are different on speed limits on small a venues and streets. This prevents vehicles to speed up or accelerate unnecessarily in our busy streets. As being monitored by traffic enforces.next
- #18 Read. Acceleration of vehicles usually changes from time to time.
- #19 A vehicle may speed up as it travels to highways or slow down as it approaches an intersection. It should also have when the stop light is red and eventually accelerate when the light turns green. We can say that most type of acceleration that we observe is not constant or none uniform due to these factors.
- #20 Read. What can you say about the readings on the speedometer during each minute?what can you infer from the data in the atble? These means that the vehicle speeds up. Every min. there is 1 km increase on the speed of the vehicle, the increase for every minute is constant. Therefore we can say that the vehicle has next
- #21 These vehicle exhibits a uniform or constant acceleration. next
- #22 Read. Just like these example. next
- #23 Read.
- #24 We have a coin, tossed it upward,does it stay up? When it reaches its maximum height, eventually it will go down. What it makes it go down? next
- #25 Gravity pulls the coin down. Things that are thrown upward will go down because of these force.
- #26 Gravity also pulls as toward the earth that’s why we are not being thrown outside the space.next
- #27 When you climb on high place , you go against gravity. When you are on a high place and you go down, you are moving toward gravity so you use less force.
- #28 Same in free falling object. Objects at free fall also exhibit uniformly accelerated motion.
- #29 Read. All objects on the earths surface ate being accelerated towards the center of the earth at the rate of 9.8 m/s2. these means that if you raise an object above the surface of the earth and drop it, the object will start from rest and its velocity will increase 9.8m/s for each sec it is falling toward the earths surface until it strikes the ground. next
- #30 Read.next
- #39 A girl diving. The mo
- #40 The motion of the girl as it dive into the water is moving along a curve path due to a natural force called gravitational force or gravity. Read. With these the motion of the girl undergoes projectile motion. next
- #44 The two picture that I’ve showed you are the types of projectiles. Read. Let us take a look at their components
- #45 Read. No resistance in any form, to simplify, we neglect air resistance next
- #46 read
- #47 We use vx to represent it. V for velocity and x for horizontal components. Read why? Because there is no external force acting along the horizontal motion. It means the acceleration does not exist.
- #50 D for distance and x for horizontal components
- #51 Read. Constant acceleration -9.8 m/s2. take note that the negative indicates the direction and the direction is downward. due to the process of gravity accelerating at 9.8 m/s2 these cause the vertical velocity to increase which makes it not constant and it is represented as next
- #53 Vy v for velocity and y for vertical component/motion. Read h for height d for distance and y for vertical component/motion. For you to understand more lets have an example
- #54 This is an example scenario of a horizontal launched projectile. Supposed you roll a marble on a frictionless table. Observe the motion of the marble as it goes down to the floor. The motion of the marble is gradually increasing from point a to point b due to the process of gravity accelerating at 9.8 m/s2 these cause the vertical velocity to increase which makes it not constant. For horizontal velocity there is an external force acting along the horizontal motion which means no acceleration resulting to a constant horizontal velocity. Let us have a sample problem to solve.
- #56 Read.
- #57 First let us illustrate the problem. A marble is from horizontally with initial velocity of 1.50 m/s2. we are going to represent it as vi next
- #58 The marble falls at 0.70 m away from the table therefore we can say that it is the horizontal distance or dx and that is again 0.70m next
- #59 We are going to find how high read or our vertical distance or dy and also if we have initial velocity ofcourse we have the final velocity before it reaches velocity.