Question

A string wrapped on a pulley of moment of inertia
T. Other end of the string is connected to block of
mass 'm' as shown. If 'm' is released from rest
then kinetic energy of block when it descends by
'h', is
(1) mgh
(2) Greater than mgh
(3) Less than mgh
(4) mgh​

Answer 1

Answer:

Explanation:

Option 3 is correct.

Initial = mgh

Final=1/2mv^2

Initial =final

Mgh=1/2mv^2

Due to friction it will be less than mgh

Answer 2

Answer:

Option 3 is the correct  answer

Explanation:

Kinetic energy: The energy that is transferred to an object is known as kinetic energy.

For example, if we want to accelerate an object, we should apply the force and applying a force requires us to do the work. After doing the work, energy will transfer to the object.  

We know that kinetic energy's formula $\mathrm{k}=\frac{1}{2} \mathrm{mv}^{2}$

Initial = mgh

Final $=\frac{1}{2} \mathrm{mv}^{2}$

Therefore,

Initial =final

$m g h=\frac{1}{2} \mathrm{mv}^{2}$

Due to friction, it will be less than mgh