Starting from rest, a 2.3x10-4 kg flea springs straight upward. While the flea is pushing off from the ground, the ground exerts an average upward force of 0.44 N on it. This force does 2.7x10-4 J of work on the flea. (a) What is the flea's speed when it leaves the ground? (b) How far upward does the flea move while it is pushing off? Ignore both air resistance and the flea's weight.

For a) I got 1.53 m/s, but I don't know how to solve for b). Please help and explain!

Thanks

3 answers

initial work=initial KE
2.7e-4=1/2 mass*(v^2) solve for v.

b. max height PE=initial KE
mgh=initial work
solve for height h.
A.
(1/2) m v^2 = 2.7*10^-4 J
(1/2) (2.3*10^-4) v^2 = 2.7*10^-4
v = 1.53 m/s agreed

B.
Work done = force * distance
2.7*10^-4 = 0.44 d
solve for d
I interpreted as rise during push, not total height