Question

State and prove law conservation of energy? *

Answer 1

Answer:

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=21mV2

K.E=21m.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=21.m.v

 K.E=