(i)Workman 1 drops a hammer, which falls to the ground.
The hammer has a mass of 2 0 kg, and is dropped from a height of 4.8 m above
the ground.
(a)Calculate the change in gravitational potential energy
of the hammer when it is dropped.
(b)Describe the energy changes from the time the hammer
leaves the hand of workman 1 until it is at rest on the ground.
(ii)Workman 2 picks up the hammer and takes it back up the
ladder to workman 1.
He climbs the first 3.0 m in 5.0 s. His total weight,
including the hammer, is 520 N.
Calculate the useful power which his legs are producing.
Answer:
(i) (a)
Mass, m=2.0 kg, height, h = 4.8m Change in gravitational potential energy
= mgh
=2 x 10 x4.8 = 96J
(b) Potential energy 
Kinetic
energy Heat and/or sound energy
(ii) Weight, mg = 520 N, height, h == 3.0 m. Time, t = 5.0
s
Useful power 
You need to login to perform this action.
You will be redirected in
3 sec
