- #1

phy

This is what I've done so far and it's not right:

E=1/2 mv^2 - GMm/2R = GMm/4R

1/2mv^2-GMm/2(5R/2) = GMm/4(5R/2)

1/2mv^2-GMm/5R = 2GMm/20R

1/2v^2 = 3GM/10R

.:v = (3GM/5R)^1/2

Clearly, this isn't the answer I should be getting. Does anybody know where I'm going wrong?