homework #3, problem #1
This problem is a bit more tricky than I remembered- here's a hint:
write out a statement for the final velocity in terms of the amount of time it will take to reach the ground.
then write down the statement of the y-position as a function of time it will take to reach the ground. Don't use the quadratic equation to solve explicitly for the amount of time! Take a close look at the two statements you have and you'll see that there is a fairly simple substitution that you can use
(both of them will have an expression that looks like v0sin(theta)t-gt^2/2).