Question

С неподвижного плота массой 200 кг на берег озера прыгнул рыбак. масса рыбака 80 кг. за 2 секунды плот проплыл по озеру 2 метра. с какой скоростью прыгнул на берег рыбак?

Answer 1

Отношение масс рано обратному отношению скоростей. масса плота в 2,5 раза больше массы рыбака, значит скорость рыбака, будет в 2,5 раза больше скорости плота.Скорость плота=2м/2с=1м/с значит скорость рыбака будет 2,5 м/с 

Answer 2

Problem Analysis

We are given that a fisherman jumps from a stationary raft with a mass of 200 kg onto the shore of a lake. The mass of the fisherman is 80 kg. The raft moves 2 meters across the lake in 2 seconds. We need to calculate the speed at which the fisherman jumped onto the shore.

Solution

To solve this problem, 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: momentum = mass × velocity.

Before the jump, the momentum of the fisherman and the raft is zero because they are stationary. After the jump, the momentum of the fisherman and the raft combined is still zero because they are both on the shore.

Let's assume the velocity of the fisherman after the jump is v. The velocity of the raft after the jump can be calculated using the equation:

mass of fisherman × velocity of fisherman + mass of raft × velocity of raft = 0

Substituting the given values:

80 kg × v + 200 kg × 0 = 0

Simplifying the equation:

80v = 0

Since the mass of the raft is much larger than the mass of the fisherman, we can assume that the velocity of the raft after the jump is negligible compared to the velocity of the fisherman. Therefore, we can ignore the term 200 kg × 0 in the equation.

Solving for v:

80v = 0

v = 0 m/s

Therefore, the fisherman jumped onto the shore with a velocity of 0 m/s.

Answer

The fisherman jumped onto the shore with a velocity of 0 m/s.