Question

A flywheel of a gasoline engine is required to give up $300$ J of kinetic energy while its angular velocity decreases from $600$ rev/min to $540$ rev/min. What moment of inertia is required?

Answer 1

$E=\frac{1}{2}I{w}_2^1-\frac{1}{2}I{w}_2^2$

$=\frac{1}{2}[w_2^1-w_2^2]$

$300=\frac{1}{2}[w_2^1-w_2^2]$

$w1=2\times \prod \times \frac{600}{60}=20\prod \frac{rad}{sec}$

$w2=2\times \prod \times \frac{540}{60}=18\prod \frac{rad}{sec}$

put the value of w1 and w2 and calculate the value of moment of Inertia