A shopper in a supermarket pushes a cart with a force of 39 N directed at an angle of 25° below the horizontal. The force is just sufficient to overcome various frictional forces, so the cart moves at constant speed.
(a) Find the work done by the shopper as she moves down a 48 m length aisle.
(b) What is the net work done on the cart? Why?
(c) The shopper goes down the next aisle, pushing horizontally and maintaining the same speed as before. If the work done by frictional forces doesn't change, would the shopper's applied force be larger, smaller, or the same? What about the work done on the cart by the shopper?
The Attempt at a Solution
a. W=39N (48m) cos-25
b. I thought that this would also be 1696.6J because work done by the shopper equals the net work done on the cart