urgent problem acceleration force vs. gravity Sorry if this is the wrong forum. I got a problem in my last physics class I am having some trouble with. A balloon goes straight up with 15m/sec. After the balloon went up 2m sb. drops a compass. But the balloon still goes up and doesn't stop. So the question is when (time) does the compass hit the bottom. So you probably need to have a equation with the acceleration force of the rising balloon and the gravity (9.8m/square second). Hope somebody can help me. Thank you very much.