Answer:
490hp
Step-by-step explanation:
Power is energy per unit of time, an in this case the energy needed is the gravitational potential energy, so we have:

Since all units are in S.I. we get our result in Watts (Joules/s). To convert to horse power (imperial), we need to know that:

Which obviously means:

So we can write:

There is also metric horse power (
), and using this value we get
, although both results are close.