A ball with a mass of 1 kg, which moves at a speed of 10 m / s, collides with a ball with a mass of 800 g, moving towards.

A ball with a mass of 1 kg, which moves at a speed of 10 m / s, collides with a ball with a mass of 800 g, moving towards. The blow is absolutely inelastic. After impact, the speed of the balls is 2m / s in the direction of the first ball. Determine the speed of the second ball before collision.

To solve the problem, we will use the law of conservation of momentum.
According to the law of conservation of momentum:
m1 * V1 – m2 * V2 = (m1 + m2) * V, from this formula we express V2:
V2 = [m1 * V1 – (1 + 0.8) * 2] / m2 = [1 * 10 – (1 + 0.8) * 2] / 0.8 = 8 [m / s].
Answer: 8 [m / s].