Question

Some kid (mass 25 kg) jumps with a velocity of 2.5 m/s horizontally off some steps (height 0.75 m) onto his heavy-duty skateboard (mass 3 kg, height 0.02 m), initially at rest. What will be his skating speed after the jump?

a) 5.0 m/s
b) 6.25 m/s
c) 4.17 m/s
d) 3.33 m/s

Answer 1

The skating speed after the jump is 2.5 m/s.

Step-by-step explanation:

To find the skateboarding speed after the jump, we can use the principle of conservation of momentum. The initial momentum of the kid and the skateboard is zero since the skateboard is initially at rest. The final momentum of the system is the product of the total mass (25 kg + 3 kg) and the final velocity.

Using the equation for conservation of momentum:
(25 kg + 3 kg) * 2.5 m/s = (25 kg + 3 kg) * v
v = (25 kg + 3 kg) * 2.5 m/s / (25 kg + 3 kg)
v = 2.5 m/s

Therefore, the skating speed after the jump is 2.5 m/s.