Two men A and B, each having a weight of 160 lb, stand on the 200-lb, cart. Each runs with a speed of 3 ft/s measured relative to the cart. Determine the final speed of the cart if
(a) A runs and jumps off, then B runs and jumps off the same end, and
(b) Both run at the same time and jump off at the same time. Neglect the mass of the wheels and assume the jumps are made horizontally.