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Year 10 Science — Motion graphs and the kinematic equations

Read velocity off the slope of a position-time graph and displacement off the area under a velocity-time graph, and use v = u + at, s = ut + ½at² and v² = u² + 2as.

Name: ________________________

Before you start

The parts of a position-time graph, each one named.

123
  1. 1. The time axis, along the bottom
  2. 2. The position axis, up the side
  3. 3. The position-time line itself

This line is straight and sloping, so the object is covering equal ground in equal times. How steeply it climbs is how fast it is going.

  1. 1.When may the three kinematic equations be used?

    • a) When the velocity stays constant through the motion
    • b) When the object is at rest
    • c) When the acceleration stays constant through the motion
    • d) For any motion whatsoever

  2. 2.A car is doing 12 m/s when the driver brakes at a steady −3 m/s² until it stops. Use v² = u² + 2as. How far does it travel while braking, in metres? Answer with a number.

  3. 3.A cart starts from rest and accelerates steadily at 2 m/s² for 5 s. Use s = ut + ½at². How far does it travel, in metres? Answer with a number.

  4. 4.A child looks at a position-time graph whose line climbs steadily and says the object must have travelled uphill. What has she misread?

    • a) The graph is not a route map — its rise shows position changing with time
    • b) A rising line means the object was slowing down
    • c) Nothing; a rising line does mean the object went uphill
    • d) The graph shows velocity up the side, not position

  5. 5.Two objects, A and B, are drawn on one position-time graph. B's line is steeper than A's. What follows?

    • a) A has the greater magnitude of average velocity
    • b) B has the greater magnitude of average velocity
    • c) The two have the same average velocity
    • d) B started further from the origin than A

  6. 6.A trolley is doing 5 m/s and accelerates steadily at 3 m/s² for 4 s. Use v = u + at. What is its final velocity, in m/s? Answer with a number.

  7. 7.Three position-time graphs are sketched below. Tap the one that shows an object at rest.

    Write the number of the part.

    123

  8. 8.On a position-time graph an object is at 30 m at 2 s and at 105 m at 5 s. What is the magnitude of its average velocity, in m/s? Answer with a number.

Answer key — Year 10 Science — Motion graphs and the kinematic equations

  1. 1. c) When the acceleration stays constant through the motion
  2. 2. 24
  3. 3. 25
  4. 4. a) The graph is not a route map — its rise shows position changing with time
  5. 5. b) B has the greater magnitude of average velocity
  6. 6. 17
  7. 7. 1 — The first graph, a flat line
  8. 8. 25