before falling back. Ignore air resistance entirely.

a) Find the initial speed of the particle. (Look up the necessary numbers.)

b) This is a problem of motion in one dimension, with a force that depends on position only. Find the time

required to reach the turning point (maximum height).

(RE is just the radius of the earth).

This seeems so simple that I must be approaching this all wrong but here goes.

a). Putting the origin at the earths surface, we get that mvo^2/2 = mgh, where h = 2RE.

Therefore rearranginf for vo we get vo = 2sqrt(gRE).

I'm skeptical whether this is right or not because this is a level 2 mechanics course, and it just seems to easy for the course and the prof.

b), We known that U(r) - U(ro) = integral from ro to r of F dr, and thet U(ro) is zero, and

U(r) = 2mgRE.

F = mg, an then setting up an equation I get mdv/dt = 2mgRE.

Does this seem right. I just feel that its no correct?