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kkernodl
#3
Feb29-12, 07:33 PM
P: 3
Quote Quote by hotvette View Post
What you need to do is find the time it takes for the range (x) to be R/2 and then find θ such that the height (y) is H.

Your expression is valid for a triangle connecting the starting point to the peak but that doesn't have anything to do with the projectile problem.
I found the position function in the x direction and set it equal to R/2. This gave me that the time, t, such that the position of x is R/2 is t=v0sin(2θ)/2gcosθ.

I can use trig identities to simplify this to t=v0sinθ/g

I can find the position function of y: Sy=v0t-4.9t2, but I'm not sure what to plug in.

I'm also very confused as to how I'm supposed to express the answer in terms of H and R, as the question specifically asks.