Two balls moving towards each other at a speed of 2m / s. and 4m / s The masses of the balls are equal

Two balls moving towards each other at a speed of 2m / s. and 4m / s The masses of the balls are equal to 150g and 50g, respectively. After the collision, the smaller ball began to move to the right with a cluster of 5 m / s. At what speed and in which direction will the large ball move?

V1 = 2 m / s.

V2 = 4 m / s.

m1 = 150 g = 0.15 kg.

m2 = 50 g = 0.05 kg.

V2 “= 5 m / s.

V1 “-?

Let us use the law of conservation of momentum in vector form when the balls collide: p1 + p2 = p1 “+ p2”, where p1, p2 are the impulses of the balls before the impact, p1 “, p2” are the impulses of the balls after the impact.

The momentum p is a vector physical quantity equal to the product of the mass of the body m by its velocity V: p = m * V.

In projections, the law of conservation of momentum will look like: m1 * V1 – m2 * V2 = m1 * V1 “+ m2 * V2”.

V1 “= (m1 * V1 – m2 * V2 – m2 * V2”) / m1.

V1 “= (m1 * V1 – m2 * V2 – m2 * V2”) / m1.

V1 “= (0.15 kg * 2 m / s – 0.05 kg * 4 m / s – 0.05 kg * 5 m / s) / 0.15 kg = – 1 m / s.

The “-” sign means that the speed of the larger ball is directed after hitting to the left.

Answer: V1 “= 1 m / s.