Question

Из неподвижной лодки, масса которой 80 кг, прыгает на берег мальчик. масса мальчика 40 кг, скорость его при прыжке 2м/с. какую скорость приобрела лодка?

Answer 1

MU=mV    80U=40*2     U=1 м/с

Answer 2

Calculation of the Boat's Velocity

To calculate the velocity acquired by the boat when the boy jumps onto the shore, we can use the principle of conservation of momentum. According to this principle, the total momentum before the jump is equal to the total momentum after the jump.

The momentum of an object is given by the product of its mass and velocity. Therefore, the momentum of the boat before the jump is equal to the momentum of the boy after the jump.

Let's denote the mass of the boat as m1 (80 kg) and the mass of the boy as m2 (40 kg). The velocity of the boy before the jump is v2 (2 m/s). We need to find the velocity of the boat after the jump, which we'll denote as v1.

Using the conservation of momentum equation, we have:

m1 * v1 = m1 * v1 + m2 * v2

Simplifying the equation, we get:

v1 = (m2 * v2) / m1

Substituting the given values, we have:

v1 = (40 kg * 2 m/s) / 80 kg

Calculating the result:

v1 = 1 m/s

Therefore, the boat acquires a velocity of 1 m/s when the boy jumps onto the shore.