Imagine a system where a block rests on an inclined plane. The block is then giv
ID: 1596519 • Letter: I
Question
Imagine a system where a block rests on an inclined plane. The block is then given an initial push so that it starts sliding down along the plane. After traveling some distance down the inclined plane it comes to rest due to frictional forces. In the simplest case, there are three forces acting upon the motion of the block—the initial push, gravity, and friction. Which of these statements about the work done by these three forces is true?
-The work done by gravity is equal to the sum of the work done by friction and the initial push.
-All three forces contribute an equal amount of work.
-The work done by friction is equal to the sum of the work done by gravity and the initial push.
-The work done by the initial push is equal to the sum of the work done by friction and gravity.
Explanation / Answer
The initial push and gravity tend to add to the KE; friction tends to reduce the KE. Therefore the first one:
The work done by friction is equal to the sum of the work done by gravity and the initial push.