From a stationary boat, the mass of which is 80 kg, a boy jumps to the shore. The boy’s weight is 40 kg

From a stationary boat, the mass of which is 80 kg, a boy jumps to the shore. The boy’s weight is 40 kg, his speed when jumping is 2 m / s. What speed has the boat gained?

According to the law of conservation of momentum:

m1V1 = m2V2, where m1 is the mass of the boat (m1 = 80 kg), V1 is the speed of the boat (m / s), m2 is the weight of the boy (m2 = 40 kg), V2 is the speed of the boy when jumping (V2 = 2 m / s) ).

Let’s express and calculate the speed of the boat:

V1 = m2V2 / m1 = 40 * 2/80 = 1 m / s.

Answer: The boat has acquired a speed of 1 m / s.