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# Motion speed velocity_ ppt.

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• 1. Motion
• 2. What is Motion?any physical movement or change in positionor place, relative to a reference point Movement Reference Point
• 3. Distance = how far an object has moved.Measured in meters, kilometers (cm or mm) If each markY Axis represents 10 cm, what is the distance between the girl and the ball? ______ X Axis
• 4. If the girl walks to the Y Axis red ball, then walks backwards to the bear, how far has she traveled? ______ X AxisDisplacement = the distance of a bodys changein position from a starting point.Her final displacement is ______ from thestarting point.
• 5. Speed = the distance an object travelsper unit of time (sec, hour, year..etc)Speed EquationSpeed (meters/second) = distance (in meters) time (sec) v=s t
• 6. A car travels a distance of 500 m in 10sec. What is the cars speed?v = s/tA second car travels a distance of 100meters in 20 seconds. What is thiscars speed?
• 7. More practice. (Speed = distance/ time)An elevator travels from the first floor to the 25thfloor of a building, a distance of 100 meters, in 30seconds. What is the elevators speed?Distance = ______Time = _______Speed = _______
• 8. Constant Speed vs Changing SpeedConstant speed means that the speed stays the samethroughout the entire distance*Very few things can stay at a constant speed. Rather,things usually move at a constant speed for a period oftime. The cyclist speeds up, slows down, stops..etc
• 9. Graphs represent speeds of objects. This graph shows a bus as it travels itsroute. Between what points is the bus accelerating? _____ & ____ Between what points is the bus moving at a constant speed? _____ & _____ Between what points is the bus stopped? __________ Between what points it the bus decelerating? _________
• 10. Average Speed = total distance traveled time takenThis is useful when you aretrying to measure speed, andthe object moved at varyingspeeds throughout thetrip. For instance, if youdrove from here to Chicago,you might AVERAGE 60mph,even though you stopped atlights, or slowed down orwhen 70 at some points onyour trip.
• 11. On graphs that show distance and time, the SLOPE of the lineis a measure of the speed of an object. Pick two points (X-value, Y-value) that are on the line. The easiest points to pick are points where the line crosses the grid of the graph paper. In this example, Point 1 could be ( 2, 400) Point 2 could be (4, 800) Plug these two points into the following formula to calculate the slope: Slope = Y2 - Y1 X2 - X1 Slope = 800 - 400 4- 2 Slope = 400 = 200 2 Speed = 200 m/min
• 12. 1. Calculate eachturtles speed:Bill ______Myrtle ______Zed ______
• 13. 2. Can you find fromthe graph, the pointwhere Zed stoppedand floated for awhile?3. Which turtle winsthe race?4. At what time periodwas Bill and Myrtlesspeed the same?
• 14. What is Velocity?Velocity is a measure of thespeed of an object AND thedirection it is moving in space.On the escalator, passengersare moving at the sameconstant speed, but they aremoving in different directions.Velocity can change even ifspeed is remaining constant(you just change direction)
• 15. Velocity = distance/time1. If a person is walking at 4 m/s, how far can he travelin 30 seconds?a) 120 meters b) 7.8 meters c) .08 meters2. A spaceship can move 100 meters in 2seconds. What is the ships velocity?a) 200 m/s b) 50 m/s c) .002 m/s3. A chicken runs across the street at a speed of 12m/s. If the road is 36 meters across, how long does ittake for the chicken to cross the road?a) 3 s b) 432 s c) .333 s
• 16. Speed is......._____________________________Velocity is .... _____________________________
• 17. Acceleration = the rate of change of velocityPositive acceleration = speeding upNegative acceleration = slowing downChange in Velocity = final velocity (vf) - initial velocity (vi)acceleration (m/s2) = (vf) - (vi) time
• 18. Change in velocity is often written asthe triangle indicates "change"acceleration = change in velocity change in time If a car moves at a constant velocity, then its acceleration is zero
• 19. Calculations1. A plane travels in a single direction on arunway. It reaches the end of the runway in 20seconds and its velocity is 80 m/s. What isits acceleration?What is the Vf? _____What is the Vi? _____2. A skateboarder is traveling at 8 m/s. He slowsand comes to a stop in 4 sec. What was theacceleration? (hint: it is a negative number)What is the Vf? _____What is the Vi? _____
• 20. 3. A sailboat is moving at 12 m/s when a gust ofwind changes its velocity to 18 m/s. The wind lasts10 seconds. For that 10 sec, what was itsacceleration?What is the Vf? _____What is the Vi? _____What is the t? _______
• 21. Think about this....What are three ways to change the velocity of a car? Accelerate Decelerate Change direction
• 22. Think about this....1. Why do highways have speed limits and not velocity limits?2. What are three ways to change the velocity of a car?3. A speed skater accelerates at 5m/s2. What will his speed be 4seconds later?
• 23. QUIZ TIME
• 24. 1. Motion indicates a change in _____________2. Motion is relative to a ______________________3. Acceleration is a change in ____________4. Speed = distance / ?5. Velocity is a measure of an objects speed andits __________________________
• 25. 6. The slope of the line on the graph will tell you the objects______________________7. The triangle in the equation represents ________8. If you are slowing down, then you have a ____________acceleration.
• 26. EQUATION: VELOCITY = distance / time9. A boat moves 100 meters in 25 seconds. What is theboats velocity.SHOW YOUR WORK by writing the equation with the numbersplugged in. (1pt)Find the correct answer (1 pt)