Name:

Kinematics Problem Set

  1. Conceptual Knowledge Questions
  1. What does it mean to say motion is relative?
  2. When describing everyday motion, what is usually used as a frame of reference?
  3. Explain the difference between average speed and instantaneous speed?
  4. Name two things that could be used to determine the instantaneous speed of a car?
  5. Explain the difference between speed and velocity.
  6. If the speedometer in your car reads a constant 40 km/h, can you say the car is traveling at a constant velocity?
  7. Name three controls in a car that allow the driver to change the velocity of the car.
  8. Speed is the rate at which ______.
  9. Acceleration is the rate at which ______.
  10. Explain how a car traveling at a constant speed in a circular path is accelerating.
  11. What is the acceleration of an object moving at a constant speed in a straight line?
  12. What is the rate of acceleration of an object experiencing free fall?
  13. For an object thrown upward,
  14. what is its speed at its highest point?
  15. What is its acceleration at its highest point?
  16. A toy rocket is launched straight up with an initial speed of 20 m/s. Neglecting air resistance, what is the velocity of the rocket as it impacts the ground?
  17. When a falling object stops accelerating it has reached ______.
  18. What causes a falling object to stop accelerating?
  19. If gravity causes all falling object to accelerate at the same rate, why do some objects fall faster than others?

1. Depends on what is used as a frame of reference. / 2. The surface of the Earth / 3. Instantaneous speed is at a given instant in time; average is over a time interval. / 4. Speedometer; radar gun / 5. Velocity has a direction.
6. No. The car could be changing directions. / 7. accelerator; brake; steering wheel / 8. distance is traveled / 9. velocity changes / 10. It is changing directions.
11. 0 m/s2 / 12. -9.8 m/s2 / 13. a) 0 m/s b) -9.8 m/s2 / 14. -20 m/s / 15. terminal velocity
16. When air resistance up equals gravity (weight) down / 17. Some object reach terminal velocity before others.
  1. Problems. Neglect air resistance when solving the following problems.
  1. (I) Concord is 35 km from MPHS. Patrick leaves school at 3:00 and reaches Concord at 3:20. What is Patrick’s average speed in km/h? m/s?
  2. (I) While traveling on an interstate highway Rebecca sets her cruise control at 90 km/h. How far will she travel in 50 minutes?
  3. (I) A car starts from rest and reaches a speed of 42 m/s over a 7.0 s period. What is the car’s acceleration?
  4. (I) What rate of acceleration is needed for an object to increase it speed from 32 m/s to 96 m/s in 8.0 seconds?
  5. (I) In a TV, an electron initially at rest leaves a cathode and is accelerated in a straight line towards an anode. It reaches the anode in 0.01 s traveling at 2000 m/s. What is the acceleration of the electron?
  6. (I) A car moving at 20 m/s is accelerated uniformly at a rate of 1.6 m/s2 for 6.8 s. What is the speed of the car at the end of the 6.8 s time period?
  7. (II) A weather balloon is floating at a constant height above the ground when it releases a pack of instruments.
  8. If the pack hits the ground at a speed of 73.5 m/s, what is the height of the balloon?
  9. How long does it take the pack to fall from the balloon to the ground?
  10. (I) A student drops a stone from a bridge 120 m high. With what velocity does the stone strike the water below?
  11. (II) A wrench falls from a helicopter rising at a constant speed of 6.0 m/s.
  12. After 2 s, what is the velocity of the wrench?
  13. After 2 s, how far below the helicopter is the wrench?
  14. (II) A car comes to a stop after a uniform deceleration of 9.0 m/s2 for 8 s. What distance is traveled by the car during this time?
  15. (I) During takeoff a plane travels a distance of 500 m while being accelerated at a rate of 5.0 m/s2. What is the speed of the plane at takeoff?
  16. (I) A stone starts from rest and falls freely for 8.0 s.
  17. Calculate the speed of the stone at the end of the 8 s.
  18. What distance does the stone travel during this time?
  19. (III) Just as a traffic light turns green, a waiting car begins to accelerate uniformly at 6.0 m/s2. At the instant the car begins to accelerate, a truck with a constant velocity of 21 m/s passes the car in the next lane traveling in the same direction as the car.
  20. How far will the car travel before it catches the truck?
  21. How fast will the car be traveling when it catches the truck?
  22. (I) Determine the displacement of a plane as it is accelerated from 66 m/s to 88 m/s in 12 s.
  23. (I) A rocket powered sled can start from rest reach a speed of 444 m/s in 1.80s and be brought to a stop again in 2.15 s.
  24. What is the acceleration of the sled when starting?
  25. What is the acceleration of the sled when braking?
  26. (III) A driver going 90 km/h suddenly sees the lights of a barrier 40.0 m ahead. It takes the driver 0.75 s before he applies the brakes and the average acceleration during braking is -10.0 m/s2.
  27. Does the car hit the barrier?
  28. How fast could the car be moving and not hit the barrier?
  29. (II) An arrow is shot straight up from a height of 1.50 m with an initial speed of 45 m/s.
  30. How long before the arrow reaches its maximum height?
  31. What is the maximum height the arrow reaches?
  32. What is the velocity of the arrow when it returns to the point where it was launched?
  33. How long after launch before the arrow returns to it original height?

1) 105 km/h or 29.2 m/s / 2) 75 km or 75,000 m / 3) 6.00 m/s2 / 4) 8.00 m/s2
5) 2 x 105 m/s2 / 6) 31 m/s / 7) a. 276 m b. 7.50 s / 8) -48.5 m/s
9) a. -14 m/s b. 20 m below the helicopter / 10) 290 m
11) 71 m/s / 12) a. 78 m/s b. 310 m / 13) a. 150 m b. 42 m/s
14) 920 m / 15) a. 247 m/s2
b. -207 m/s2 / 16) a. yes b. 22 m/s / 17) a. 4.59 s b. 103 m
c. -45.0 m/s d. 9.18 s