 ### Linear Momentum & Impulse Homework

1. An 8 N force acts on a 5 kg object for 3 sec. What impulse is given the object? What change in momentum does this impulse cause? If the object’s initial velocity was 25 m/s. what is its final velocity? Ans: 24 Nsec; 24 Nsec; 29.8 m/s
2. A 6 N force acts on a 3 kg object for 10 sec. What will be the final velocity of the object if its initial velocity was 10 m/s? Ans: 30 m/s
3. A 20,000 N truck is acted upon by a force that decreases its speed from 10 m/s to 5 m/s in 5 sec. What is the magnitude of the force? Ans: -2040.82 N
4. A 2000 N force acts on a rocket of mass 1000 kg, increasing its speed from rest to 200 m/s. How long did the force act? Ans: 100 sec
5. A 700 kg car moving at 20 m/s collides with a stationary truck with mass 1400 kg. The two vehicles interlock as a result of the collision. What is the velocity of the car/truck? Ans: 6.67 m/s
6. A rocket sits on a launch pad loaded with fuel. The igniter causes the rocket to rise off the pad, oxidizing 100 g of fuel and ejecting it out the back of the rocket at -650 m/s. After launch, the rocket has a mass of 3 kg. What is its speed after launch? Ans: +21.67 m/s
7. A 15 g pellet moving at 600 m/s hits a stationary 100 g block and becomes embedded in the block. With what speed do they move off together? Ans: 78.26 m/s
8. A 0.5 kg ball traveling at 6 m/s collides head-on with a 1 kg ball moving in the opposite direction at 12 m/s. The 0.5 kg ball moves away at 14 m/s in the opposite direction after the collision. Find the velocity of the 1 kg ball after the collision. Ans: -2 m/s
9. A plastic ball of mass 0.2 kg moves at 0.6 m/s, east. It collides with a 0.1 kg ball moving at 0.8 m/s, west. After the collision, the velocity of the 0.1 kg ball is 0.6 m/s, east. What is the velocity of the 0.2 kg ball after the collision? Ans: 0.1 m/s, west
10. A 25 g ball moving at 10 m/s, right, collides head-on with a 50 g ball moving at 3 m/s, left. After the collision, the 25 g ball moves at 6 m/s, left. What is the velocity of the 50 g ball after the collision? Ans: 5 m/s, right
11. A 3 kg can containing a 100 g firecracker is thrown into the air. The firecracker explodes, exiting the can at 25 m/s. What is the speed of the can after the collision? Ans: -0.83 m/s
12. A thread holds two carts together that are separated by a compressed spring. The thread is broken. One cart, with mass of 1.5 kg, moves with a velocity of 27 cm/s to the left. What is the velocity of the other cart with mass of 4.5 kg? Ans: 0.09 m/s, right