Name:
Kinematics Problem Set
A. Conceptual Knowledge Questions (1-D Kinematics)
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 ______changes.
9. Velocity is the rate at which ______changes.
10. Acceleration is the rate at which ______changes.
11. Explain how a car traveling at a constant speed in a circular path is accelerating.
12. What is the acceleration of an object moving at a constant speed in a straight line?
1. It depends on what is used as a frame of reference. / 2. the Earth’s surface/ 3. Instantaneous speed is at a given instant in time; average is calculated over a time interval. / 4. speedometer; radar gun
5. Velocity has a direction. (Speed is a scalar; velocity is a vector.) / 6. No. The car could be changing directions. / 7. accelerator; brake; steering wheel / 8. distance
9. position/displacement / 10. velocity / 11. It is changing directions. / 12. 0 m/s2
B. Problems (General 1-D Kinematics)
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) You are walking at a constant velocity of 2 m/s to the left while riding on a train that is moving at 12 m/s to the right.
a. What is your velocity relative to the train?
b. What is your velocity relative to the ground?
4. (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?
5. (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?
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 car comes to a stop after a uniform deceleration of 9.0 m/s2 for 8.0 s. What distance is traveled by the car during this time?
8. (II) During takeoff a plane (initially at rest) 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?
9. (II) Determine the displacement of a plane as it is accelerated from 66 m/s to 88 m/s in 12 s.
10. (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.
a. What is the acceleration of the sled when starting?
b. What is the acceleration of the sled when braking?
1) 105.0 km/h or 29.17 m/s / 2) 75.00 km or 7.500 x 104 m / 3) a. 2.000 m/s leftb. 10.00 m/s right / 4) 6.000 m/s2
5) 8.000 m/s2 / 6) 30.88 m/s / 7) 288.0 m / 8) 70.71 m/s
9) 924 m / 10) a. 246.7 m/s2 b. −206.5 m/s2
C. Conceptual Knowledge Questions (Free Fall Motion)
1. What is the rate of acceleration of an object experiencing free fall?
2. For an object thrown upward,
a. what is its speed at its highest point?
b. what is its acceleration at its highest point?
3. 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?
4. When a falling object stops accelerating it has reached ______.
5. What causes a falling object to stop accelerating?
6. If gravity causes all falling object to accelerate at the same rate, why do some objects fall faster than others?
1. −9.8 m/s2 / 2. a) 0 m/s b) −9.8 m/s2 / 3. −20 m/s4. terminal velocity
/ 5. When air resistance pushing up equals the force of gravity pulling down on an object. / 6. Some objects reach terminal velocity before others.
D. Problems (Free Fall Motion). Neglect air resistance when solving the following problems.
1. (I) A student drops a stone from a bridge 120 m high.
a. With what velocity does the stone strike the water below?
b. How long does it take the stone to reach the water below?
2. (I) A stone starts from rest and falls freely for 8.0 s.
a. Calculate the speed of the stone at the end of the 8 s.
b. What distance does the stone travel during this time?
3. (II) A weather balloon is floating at a constant height above the ground when it releases a pack of instruments.
a. If the pack hits the ground at a speed of 73.5 m/s, what is the height of the balloon?
b. How long does it take the pack to fall from the balloon to the ground?
4. (II) A wrench falls from a helicopter rising at a constant speed of 6.0 m/s.
a. After 2 s, what is the velocity of the wrench?
b. After 2 s, how far below the helicopter is the wrench?
5. (II) An arrow is shot straight up from a height of 1.50 m with an initial speed of 45 m/s.
a. How long before the arrow reaches its maximum height?
b. What is the maximum height the arrow reaches?
c. What is the velocity of the arrow when it returns to the point where it was launched?
d. How long after launch does the arrow returns to its original height?
1) a. −48.50 m/s b. 4.949 s / 2) a. 78.4 m/s b. 313.6 m / 3) a. 275.6 m b. 7.50 s / 4) a. −13.60 m/s b. 19.60 m below the helicopter5) a. 4.592 s b. 104.8 m c. −45 m/s d. 9.184 s