Let’s say you push the block from the bottom of the plane allthe way up to the top of the plane, then let it slide backdown.
11-1. While you are pushing the block up the plane, is the workdone by gravity positive or negative? Why?
11-2. While you are pushing the block up the plane, is the workdone by friction positive or negative? Why?
11-3. As the block slides back down the plane, is the work doneby gravity positive or negative?
11-4. As the block slides back down the plane, is the work doneby friction positive or negative?
11-5. What is the net work done by gravity over the entire cycle(being pushed all the way up and then sliding all the way backdown)? Is it positive, negative, or zero?
11-6. What is the net work done by friction over the entirecycle (being pushed all the way up and then sliding all the wayback down)? Is it positive, negative, or zero?