Momentum and Collision Practice Problems and Answers

PROBLEM 1 A 2250 kg pickup truck has a velocity of 25 m/s to the east. What is the momentum of the truck?

PROBLEM 2 What velocity must a car with a mass of 1210 kg have in order to have the same momentum as the pickup truck?

PROBLEM 3 A baseball of mass 0.14 kg is moving at 35 m/s. A) Find the momentum of the baseball. B) Find the velocity of a bowling ball, mass 7.26 kg, would have if its momentum is the same as the baseball.

PROBLEM 4 A compact car, mass 725 kg, is moving at 60 m/s. A) Find its momentum. B) At what velocity is the momentum of a larger car, mass 2175 kg, equal to that of the smaller car?

PROBLEM 5 A snowmobile has a mass of 250 kg. A constant force is exerted on it for 60 s. The snowmobile’s initial velocity is 6 m/s and its final velocity is 28 m/s. A) what is the change in momentum? B) what is the magnitude of the force exerted?

PROBLEM 6 The brakes exerted a 640 N force on a car weighing 15689 N and moving at 20 m/s. The car finally stops. A) What is the car’s mass? B) What is the car’s initial momentum? C) What is the change in the car’s momentum? D) How long does the braking force act on the car to bring it to a halt?

PROBLEM 7 What impulse is needed to stop a 45 g mass traveling at 42 m/s?

PROBLEM 8 Which has the greater momentum: a 145 g baseball traveling at 40 m/s or 45 g golf ball traveling at 67 m/s?

PROBLEM 9 A force of 540 N is used to stop an object with a mass of 65 kg moving at 175 m/s. How long will it take to bring the object to a full stop?

PROBLEM 10 In hitting a stationary hockey puck having a mass of 180g, a hockey player gives the puck an impulse of 6 N*s. At what speed will the puck move toward the goal?

Before Collision After Collision Person 60 * v Medicine ball 300 15 * v Total

Before Collision After Collision Granny 80 * 6 = 480 80 * v Ambrose 40 * v Total 480

Before Collision After Collision Truck 3000 * 10 = 30 000 3000 * v Car 1000 * 15 = 15 000 Total 30 000

PROBLEM 11 Glider A of mass .355 kg moves along a frictionless air track with a velocity of .095 m/s. It collides with a glider B of mass .710 kg moving in the same direction at a speed of .045 m/s. After collision glider A continues in the same direction with a velocity of .035 m/s. What is the velocity of glider B after collision?

PROBLEM 12 A .105 kg hockey puck moving at 48m/s is caught by a 75kg goalie at rest. With what speed does the goalie slide on the ice?

PROBLEM 13 A 35 g bullet strikes a 5 kg stationary wooden block and embeds itself in the block. The block and the bullet fly off together at 8.6m/s. What is the original velocity of the bullet?

PROBLEM 14 A 35 g bullet moving at 475m/s strikes a 2.5 kg wooden block. The bullet passes through the block, leaving at 275 m/s. The block was at rest when it was hit. How fast is it moving when the bullet leaves ?

PROBLEM 15 An astronaut at rest in space with mass 84kg fires a thruster that expels 35g of hot gas at 875m/s. What is the velocity of the astronaut after the firing shot?

PROBLEM 16 A 4 kg model rocket is launched, shooting 50g fuel from its exhaust at an average velocity of 625 m/s. What is the velocity of the rocket after the fuel has burned? (Ignore effects of gravity and air resistance)

PROBLEM 17 Two campers dock a canoe. One camper steps on the dock. This camper has a mass of 80 kg and moves forward at 4 m/s. With what speed and direction do the canoe and the other camper move if their combined mass is 110 kg?

PROBLEM 18 Two students on roller skates stand face to face, then push each other away. One student has a mass of 90 kg, the other 60 kg. Find the ratio of their velocities just after their hands lose contact. Which student has the greater speed?

PROBLEM 19 Block A with a mass 12 kg moving at 2.4 m/s makes a perfect elastic head-on collision with a block B, mass 36 kg, at rest. Find the velocities of the two blocks after collision. Assume all motion is in one dimension.

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PROBLEM 20 A 2575 kg van runs into the back of a 825kg compact car at rest. They move off together at 8.5 m/s. Assuming no friction with the ground, find the initial speed of the van.

PROBLEM 21 A 5g bullet is fired with a velocity of 100 m/s toward a 10 kg stationary solid lock resting on a frictionless surface. What is the change in momentum of the bullet if it becomes embedded in the block?

PROBLEM 22 A 50 g ball is struck with a club. The force on the ball varies from zero when contact is made up to some maximum value (when the ball is deformed) and then back to zero when the ball leaves the club. Assume the ball leaves the club face with a velocity of +44 m/s. Estimate the impulse due to the collision.

PROBLEM 23 In a particular car test, a 1.50 x 103 kg automobile collides with a wall. The initial and final velocities of the automobile are –15 m/s and 2.6 m/s respectively. If the collision lasts for 0.150s, find the impulse due to collision and the average force exerted on the automobile.

PROBLEM 24 A baseball player attempts to use a pitching machine to help him improve his batting average. He places the 50 kg machine on a frozen pond. The machine fires a 0.15 kg baseball horizontally with a speed of 36 m/s. What is the recoil velocity of the machine?

PROBLEM 25 An 1800 kg luxury sedan stopped at a traffic light is struck from the rear by a compact car with a mass of 900 kg. The two cars became entangled as a result of the collision. If the compact car was moving at a velocity of +20 m/s before the collision, what is velocity of the entangled mass after the collision?