A 1500kg car moving at a speed of 20 m/s comes to a halt. How much work was done by the brakes?

How fast can a 2.0 horsepower motor lift a 200 kg mass?

A boy with a mass of 20 kg is riding on a 10 kg cart which is travelling at 3 m/s. He jumps off in such a way that he lands on the ground with no horizontal speed. What was the change of speed of the cart?

not sure how to solve please help

3 answers

1. Work = 0.5M*V^2 = 0.5*1500*20^2 =
300,000 J.

2. hp * 746W/hp = 1492 Watts=1492J/s.

P = F*V = Mg * V = 1492 J/s.
200*9.8 * V = 1492
1960V = 1492
V = 0.76 m/s.

thank you for the help

Glad I could help.