Question

1. What is the momentum in kgm/s of a 10 kg truck traveling at 5 m/s?

2. What is the momentum of a bullet of mass 50g travelling at 300 m/s?

3. What is the momentum of a dog (mass 12 kg) fired out of a canon at 120 m/s?

4. George, whose mass is 48 kg, is running at 5 m/s and jumps onto a 7 kg skateboard moving in the same direction at 3.0 m/s. What is their speed after George is on the skateboard?

5. A truck of mass 500 kg moving at 4 m/s to the right collides with another truck of mass 1500 kg moving at 1.5 m/s to the left. What is their common velocity after the collision if they stick together? (Hint: Make one of the velocities negative and do a sketch to show what is happening)

6. Chae is standing still and fires a rifle. The bullet has a mass of 0.045 kg and is travelling at 350 m/s. If Chae has a mass of 60 kg, with what velocity does he move backwards.

Difficult question for physics geniuses only

7. A comet of mass 1 x 106 kg hits the earth at a speed of 1 x 105 m/s. At what speed does the earth move backwards after the collision (mass of earth = 700 x 1022 kg)? (Assume that the earth is not moving before the collision, a big assumption!)

Answer 1

Answer:

1. p =mv

Momentum = 10×5 = 50kgm/s

2. p =mv

Momentum = 0.05× 300 = 15kgm/s