Law of conservation of momentum
1. A hand gun has a mass of 1.5 kg, and a bullet has a mass of 0.016 kg. If the gun recoils at
-3.2 m/s, calculate the velocity of the bullet.
2. Two ice skaters, who are initially stationary, push apart. Skater A has a mass of 72 kg,
and skater B has a mass of 64 kg. Skater A moves lest with a velocity of -0.2 m/s.
Calculate the velocity of skater B after pushing apart.
3. Object 1 has a mass of 3.0 kg and is travelling with a velocity of 2.4 m/s. It collides with
a stationary object 2, with a mass of 1.5 kg. After collision, object 1 has a velocity of 1.0
m/s. Calculate the velocity of object 2.
1
4. Two objects with mass 10.0 kg and 5.0 kg, and velocities 3.0 m/s and -2.0 m/s,
respectively, collide. Both objects stick and move off together. Calculate the combined
velocity they have after collision.
5. A raft of mass 180 kg carries two swimmers of mass 50. kg and 80. kg. The raft is
initially floating at rest. The two swimmers simultaneously dive off opposite ends of the
raft, each with a horizontal velocity of 3 m/s. With what velocity and in what direction
does the raft start to move?
2