physics
posted by Sarah on .
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.

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.