Question

A rectangular crate of weight W is floating in water with 2/3 of its volume above water. If you now want to push down on it to hold it lower in the water, so that only 1/3 of its volume is above water, the downward force needed to do this is:

A. W
B. 2W
C. W/2
D. W/3

I have no idea what equation to use to help solve this problem. Could someone point me in the right direction..
Thanks in advance.

Answer 1

The volume submerged call it x. Now the weight of the water displaced is equal to the weight of the crate...W. So if you increase the weight by W , for a total of 2W, the new volume displaced is 2x

So F must be W.