physics
posted by Alexandra .
An object of mass 5 kg is dropped from a certain height. Just before it strikes the ground it has a kinetic energy of 1250 J. From what height was the object dropped? Ignore air resistance and use g = 10 m/s2.

PE at start=KE at end
mgh=final KE
solve for h 
a body is thrown up with a velocity of 20 m/s . calculate the maximum height attained by the body.