Request a call back

Join NOW to get access to exclusive study material for best results

CBSE Class 9 Answered

(a)State Law of Conservation of Energy and express it in the form of an equation for a body
of mass m falling from a point A at height h, above the ground at
(i) A (ii) B at a height from ground, (iii) C.

Asked by sahasra4050 | 20 Jan, 2022, 08:53: AM
Expert Answer

Law of conservation of energy - Energy can neither be created nor be destroyed; it can only be transformed from one form to another.

Consider a body of mass m placed at A.

h = AB is the height of the body above the ground

u = 0 is initial velocity at A

v1 = velocity of body at C

v = velocity of body at B, i.e., just above the ground

(i) At point A

PEA = mgh

KEA = 0

Total mechanical energy at A, EA = PEA + KEA = mgh + 0 = mgh

(ii) At point C

v12-0 = 2gs

v12 = 2gs

KEC = 

PEC = mg(h-s)

Total mechanical energy at C, EC = PEC + KEC = mg(h-s) + mgs = mgh

(iii) At point B

v2-02 = 2gh

v2 = 2gh

KEB = 

PEB = 0

Total mechanical energy at B, EB = PEB + KEB = 0 + mgh = mgh

The total mechanical energy of the body at A, B and C (also at any other point in the path AB) is the same. So, the total mechanical energy of the body throughout the free fall is conserved.

 
Answered by Shiwani Sawant | 20 Jan, 2022, 09:18: AM
CBSE 9 - Physics
Asked by pramodkumardalal711 | 18 Jun, 2022, 10:19: AM
ANSWERED BY EXPERT
CBSE 9 - Physics
Asked by divyanshu.3082007 | 03 Feb, 2022, 05:21: PM
ANSWERED BY EXPERT
CBSE 9 - Physics
Asked by topperlearningforcontent | 31 Jan, 2022, 10:14: AM
ANSWERED BY EXPERT
CBSE 9 - Physics
Asked by tajbindarkaurs | 14 Nov, 2021, 10:19: AM
ANSWERED BY EXPERT
CBSE 9 - Physics
Asked by atiquzzaman100 | 21 Oct, 2021, 01:35: PM
ANSWERED BY EXPERT
CBSE 9 - Physics
Asked by kaziryan.05 | 19 May, 2021, 07:43: AM
ANSWERED BY EXPERT
CBSE 9 - Physics
Asked by harikishortomar | 03 Jan, 2021, 10:52: PM
ANSWERED BY EXPERT
×