Question

If the angular momentum of a rotating body about a fixed axis is increased by 10%. It's kinetic energy will be increased

Answer 1

Answer: The correct answer is 20%.

Explanation:

The expression for the rotational kinetic energy in terms of angular momentum and moment of inertia is as follows;

$K=\frac{L^{2}}{2I}$

Here, K is the rotational kinetic energy, L is the angular momentum and I is the moment of inertia.

Calculate the change in rotational kinetic energy.

$\frac{\Delta K}{K}=2(\frac{\Delta L}{L})100$

It is give in the problem that the angular momentum of a rotating body about a fixed axis is increased by 10%.

Put $\frac{\Delta L}{L}=10 percentage$.

$\frac{\Delta K}{K}=2(10 percentage)$

$\frac{\Delta K}{K}=20 percentage$

Therefore, the increase in the kinetic energy is 20%.