1. An ostrich with a mass of 146 kg is running to the right with a velocity of 17 m/s. Find the momentum of the ostrich.
2. A 21 kg child is riding a 5.9 kg bike with a velocity of 4.5 m/s to the northwest.
a. What is the total momentum of the child and the bike together?
b. What is the momentum of the child?
c. What is the momentum of the bike.?
3. What velocity must a car with a mass of 1210 kg have in order to have the same momentum as the pickup truck in Sample Problem 6A?
Practice 6B
1. A 0.50 kg football is thrown with a velocity of 15 m/s to the right. A stationary receiver catches the ball and brings it to rest in 0.020 s. What is the force exerted on the receiver?
2. An 82 kg man drops from rest on a diving board 3.0 m above the surface of the water and comes to rest 0.55 s after reaching the water. What force does the water exert on him?
3. A 0.40 kg soccer ball approaches a player horizontally with a velocity of 18 m/s to the north. The player strikes the ball and causes it to move in the opposite direction with a velocity of 22 m/s. What impulse was delivered to the ball by the player?
Practice 6C
1. How long would it take the car in Sample Problem 6C to come to a stop from 20,0 m/s to the west? How far would the car move before stopping? Assume a constant acceleration.
2. A 2500kg car traveling to the north is slowed down uniformly from an initial velocity of 20.0 m/s by a 6250 N braking force acting opposite the car’s motion. Use the impulse- momentum theorem to answer the following questions:
a. What is the car’s velocity after 2.50 s?
b. How far does the car move during 2.50 s?
c. How long does it take the car to come to a complete stop?
3. Assume that the car in Sample Problem 6C has a mass of 3250 kg.
a. How much force would be required to cause the same acceleration as in item 1? Use the impulse-momentum theorem.
b. How far would the car move before stopping?
Practice 6D
1. A 63.0kg astronaut is on a space walk when the tether line to the shuttle breaks. The astronaut is able to throw a 10.0 kg oxygen tank in a direction away from the shuttle with a speed of 12.0 m/s, propelling the astronaut back to the shuttle. Assuming that the astronaut starts from rest, find the final speed of the astronaut after throwing the tank.
2. An 85.0 kg fisherman jumps from a dock into a 135.0 kg rowboat at rest on the west side of the dock. If the velocity of the fisherman is 4.30 m/s to the west as he leaves the dock, what is the final velocity of the fisherman and the boat?