Question

a 50kg person is standing still in ice skates throws their 2.0kg helmet to the right at 25m/s while on a friction less surface. what is the final speed of the person

Answer 1

Answer:

Vp = 1 [m/s]

Explanation:

In order to solve this problem, we must use the principle of conservation of the amount of movement. In the same way, analyze the before and after of the actions.

The moment before

The 50kg person is still hold (no movement) with the 2kg helmet

The moment after

The helmet moves at 25[m/s] in one direction, the person moves in the opposite direction, due to the launch of the helmet.

In this way we can apply the principle of conservation of movement, expressing the before and after. To the left we have the before and to the right of the equal sign we have the after.

Σm*V1 = Σm*V

where:

m = total mass = (2 + 50) = 52[kg]

V1 = velocity before the lunch = 0

(50 + 2)*V1 = (25*2) - (Vp*50)

0 = 50 - 50*Vp

50 = 50*Vp

Vp = 1 [m/s]