A boy weighing 35 kg, running at a speed of 2 m / s, jumps onto a non-movable skateboard weighing 5 kg.

A boy weighing 35 kg, running at a speed of 2 m / s, jumps onto a non-movable skateboard weighing 5 kg. what speed will the skateboard gain

Initial data: m1 (boy’s weight) = 35 kg; V1 (initial speed of movement of the boy) = 2 m / s; m2 (skateboard weight) = 5 kg; V2 (starting speed of the skateboard) = 0 m / s.

Determine the speed that the skateboard will acquire from the following equality (the law of conservation of momentum):

m1 * V1 + m2 * V2 = (m1 + m2) * V1.2.

m1 * V1 = (m1 + m2) * V1.2.

V1.2 = m1 * V1 / (m1 + m2).

Payment:

V1.2 = 35 * 2 / (35 + 5) = 1.75 m / s.

Answer: The skateboard on which the boy will ride will acquire a speed of 1.75 m / s.