Name: ______
Newton’s Laws Review
BE SURE TO SHOW ALL WORK FOR THESE QUESTIONS!!!
1. A shot put with a mass of 2.0 kg is dropped on a person’s foot. Another person drops a similar sized ball with a mass of 1.0 kg on their foot. Which person will be screaming louder? Explain using the term “FORCE”. (Hint: Think about the equation for force to help you answer this question.)
2. A bug with a mass of 5.0 grams flies into the windshield of a moving 1000kg bus. Which will have the most force on impact? Which will have the greatest acceleration?
3. A 3.0 kg toy is pulled by a force of 24 N. If the toy starts from rest, how far will it travel in the first 5.0 seconds? (1.0 x 102 m)
4. Your new motorcycle weighs 2450 N. What is its mass in kg? (2.50 x 102 kg)
5. Determine the applied force required to accelerate a 3.25-kg object rightward with a constant acceleration of
1.20 m/s2 if the force of friction opposing the motion is 18.2 N. (Neglect air resistance.) (22.1 N)
6. A 0.250-kg rightward moving air track glider decreases its speed from 0.872 m/s to 0.798 m/s over the length of a 1.71 m long air track. What is the size and direction of the force that acted on the car? (0.00900 N [left])
7. In bench pressing 1.00 x 102 kg, a weight lifter applies a force of 1040 N. How large is the upward acceleration of the weight during the lift? (0.59 m/s2)
8. A gardener pushes down along the handle of a lawn mower of 20 kg mass with a force of 150 N. The handle makes an angle of 60.0° with the ground. Calculate the instantaneous acceleration of the mower if the frictional force between the wheels and the ground is 25 N. (2.5 m/s2)
9. A 40.0 N block is moving at a constant velocity along a smooth wooden tabletop.
a) A horizontal force of 14.0 N is exerted. What is the coefficient of friction between the block and the tabletop? (0.350)
b) If a 20.0 N brick is placed on the block, what force will be required to keep the block and brick moving at a constant velocity? (21.0 N)
10. A car is traveling along a highway at 90.0 km/h. The driver spots a stalled car and some traffic congestion ahead, and so applies the brakes until he skids to a stop. The coefficient of friction between the road and the 1050 kg car is 0.82.
a) What is the size and direction of the force of friction that the road exerts on the car? (8400 N)
b) What would be the size and direction of the acceleration of the car? (-8.0 m/s2, 8.0 m/s2 [back])
c) How far does the car travel before stopping? (39 m)
11. A 2.00 x 102 kg crate is pushed horizontally with a force of 7.00 x 102 N to accelerate the crate at 1.5 m/s2.
a) How large is the frictional force? (400 N)
b) What is the coefficient of friction? (0.20)
12. What is the coefficient of friction between a 65 kg roller skater and the floor of a roller rink if the skater moves with a constant force (at a constant speed) of 75 N? (0.12)
13. Two boys, one with a mass of 60.0 kg and the other with a mass of 90.0 kg, are standing side by side in the middle of an ice rink. One of them pushes the other with a force of 360 N for 0.10 s. Assuming that the ice surface is frictionless:
a) What is the acceleration of each boy? (6.0 m/s2, 4.0 m/s2)
b) What speed will each boy reach after the 0.10 s? (0.60 m/s, 0.40 m/s)
c) Does it matter which boy did the pushing? Explain, using Newton’s Laws of Motion.