Help please?

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1 Answer
Mar 11, 2018

D

Explanation:

We know that work is total force times distance traveled.

There's a few we can immediately eliminate:
We know that the ball has weight, so it isn't a.
The ball is traveling, so we know it travels a distance, i.e. it's not e.

We can easily realize that b and c are pretty much the same statement: kinetic energy is changing into potential energy to change magnitude. But we can have a system without work that does this, such as throwing a ball in the air. Therefore, b and c are not the answer.

D is the answer because we can express the work as
#dW = vec F cdot d vec x #
and the inner product is 0 since the forces are all vertical.

(I'm a physics major and this is a confusingly worded question)