Question

A uniform metre scale of mass 2 kg is
suspended from one end. If it is displaced
through an angle 60° from the vertical, the
increase in its potential energy is,
1)4.9 J
2 )9.8J
3) 9.8√3J. 4 ) (2-√3)J.​

Answer 1

Answer: 4.9J

Explanation:

Change in P.E = mgL(1-cos A)

Where L is the length of the rod.

Here, the mass of the scale is concentrated at the mid-point of the scale.

Therefore, here, change in P.E = mgL/2 (1-cosA)

Where,

m= 2kg

g= 9.8 m/s^2. [Given]

L= 1m

A=60°; cos 60°= 1/2

Substituting the values we get,

2 x 9.8 x 1/2 (1-1/2)

= 2 x 4.9 x 1/2

= 4.9

Therefore, the change in potential energy of the metre scale is 4.9J.

Answer 2

Explanation:

hdhdhshssdugi ivd i dg j jie kviiibeyoegb