Two bodies with masses of 200g and 300g, flying at speeds of 10m / s and 5m / s, collide with absolutely

Two bodies with masses of 200g and 300g, flying at speeds of 10m / s and 5m / s, collide with absolutely no elasticity and continue to move as a whole. Determine their overall speed if, before the collision, they flew a) in the same direction. b) towards each other.

two bodies with masses of 200g and 300g flying at speeds of 10m / s and 5m / s collide in a very non-elastic manner and continue to move as a whole. Determine their overall speed if, before the collision, they flew a) in the same direction. b) towards each other.

m1 = 200 g = 0.2 kg.

m2 = 300 g = 0.3 kg.

V1 = 10 m / s.

V2 = 5 m / s.

V -?

For absolutely inelastic impact, the law of conservation of momentum is valid in vector form: m1 * V1 + m2 * V2 = (m1 + m2) * V.

Let’s draw the coordinate axis in the direction of the motion of the first body.

1) Bodies move in one direction.

m1 * V1 + m2 * V2 = (m1 + m2) * V.

V = (m1 * V1 + m2 * V2) / (m1 + m2).

V = (0.2 kg * 10 m / s + 0.3 kg * 5 m / s) / (0.2 kg + 0.3 kg) = 7 m / s.

2) Bodies move in the opposite direction.

m1 * V1 – m2 * V2 = (m1 + m2) * V.

V = (m1 * V1 – m2 * V2) / (m1 + m2).

V = (0.2 kg * 10 m / s – 0.3 kg * 5 m / s) / (0.2 kg + 0.3 kg) = 1 m / s.

The bodies will move in the direction of motion of the first body with a speed of V = 1 m / s.