Question

state the law of conservation of energy and verify that this law is appicable for a body falling from certain height​

Answer 1

Law of conservation of energy states that:−

Energy can neither be created nor be destroyed.

Energy transforms from one form to another form and, potential energy+ kinetic energy= constant

Proof:−

At point A

K.E=0m/s

P.E=mgh

P.E=mgh

At point B,

K.E.,

2gh=V²−O²

V² =2gx

K.E=1/2mV²

K.E= 1/2 m.2gx

K.E=mgx-----------------------------(1)

P.E=mgh

P.E=m.g.(h−x)

P.E=mgh−mgx---------------------(2)

from(1) and (2)

K.E+P.E constant

mgx+mgh−mgx=mgh

mgh=mgh

At point C,

P.E=0

2gh=v²−u² ( initial velocity =0 m/s)

2gh=v²

K.E=1/2.m.v

K.E=1/2.m.2gh

K.E=mgh

Thus, in all the points the energy is same.