Question

A 500 kg cart is rolling to the right at 1.3 m/s. a 60 kg man is standing on the right end of the cart. what is the speed of the cart if tha man suddenly starts running to the left with a speed 10.0 m/s relative to the cart

Answer 1

Answer:

P1 = 1.3 (500 + 60) = 728 kg-m      total momentum to right at start

P2 = (v2 - 10) 60 + 500 v2

total momentum after running at -10 with respect to cart = 728 where v2 is the new speed of the cart

728 = 560 v2 - 600

v2 = 1328 / 560 = 2.37 m/s    new speed of cart

Check:

After:    p2 for cart = 500 * 2.37 = 1186

p1 for man = (2.37 - 10) * 60 = -458

P2 = p1 + p2 = 728       total momentum unchanged