Question

Show that the total mechanical energy is always conserved in the case of a freely falling body under gravity from a height ‘h’ by finding it when:
(i) The body is at the top.
(ii) The body has fallen a distance x.
(iii) The body has reached the ground. (air resistance neglected)

Answer 1

Answer:

Total mechanical energy is always conserved

Explanation

At height h :

PE=mgh

KE=1/2 mv2 (but as v=0 KE=0)

At height x:

PE=mg(h-x)

=mgh-mgx