Question

На рельсах стоит тележка массой 100 кг.бегущий вдоль рельсов школьник массой 50 кг с разбега запрыгнул на эту тележку после чего она вместе со школьником стала двигаться со скоростью 2м/с. чему была равна скорость школьника непосредственно перед прыжком

Answer 1

M1*V1=(m1+m2)*V
V1=(m1+m2)*V/m1=(50+100)*2/50=6 м/с

Answer 2

Calculation of the Schoolboy's Velocity

To determine the velocity of the schoolboy immediately before jumping onto the cart, 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, we can write the equation:

Total momentum before jump = Total momentum after jump

The total momentum before the jump is the momentum of the cart, which is initially at rest. The total momentum after the jump is the combined momentum of the cart and the schoolboy.

Let's denote the mass of the cart as m1 (100 kg) and the mass of the schoolboy as m2 (50 kg). The velocity of the cart before the jump is 0 m/s, and the velocity of the cart and the schoolboy after the jump is 2 m/s.

Using the equation of conservation of momentum, we can write:

m1 * v1 = (m1 + m2) * v2

where: - m1 is the mass of the cart (100 kg) - v1 is the velocity of the cart before the jump (0 m/s) - m2 is the mass of the schoolboy (50 kg) - v2 is the velocity of the cart and the schoolboy after the jump (2 m/s)

Substituting the given values into the equation, we can solve for v2:

100 kg * 0 m/s = (100 kg + 50 kg) * v2

Simplifying the equation:

0 = 150 kg * v2

Dividing both sides of the equation by 150 kg:

v2 = 0 m/s

Therefore, the velocity of the schoolboy immediately before jumping onto the cart is 0 m/s.