Question

Explain:the total mechanical energy of a free falling object always remains contact

Answer 1

CONSIDER AN OBJECT  OF MASS "m"  situated at position "a" at a height  "h" from ground.

at position "a"

PE=mgh

ke=0

te=ke+pe

te=0+mgh=mgh

at point b

pe=0

ke=1/2mv2

but v2=u2+2as

u=0

a=g

s=h

v2=0+2gh

1/2m multiplied by 2gh=mgh

2&2 cancel

te=pe+ke

0+mgh=mgh

hence proved