Question

An energy storage system based on a flywheel (a rotating disk) can store a maximum of 4.1 MJ when the flywheel is rotating at 14000 revolutions per minute.

Answer 1

Incomplete question.The complete question is here

An energy storage system based on a flywheel (a rotating disk) can store a maximum of 4.1 MJ when the flywheel is rotating at 14000 revolutions per minute.What is the moment of inertia of the flywheel?

Answer:

Moment of inertia=3.82 kg.m²

Explanation:

Given data

Energy E=4.1 MJ=4.1×10⁶J

Angular speed ω= 14000 rev/min= 14000×2π/60=1465.3 rad/s

To find

Moment of Inertia

Solution

A rotating flywheel must store its energy as kinetic energy

Let I be moment of inertia of the flywheel.We Know

$E(Energy)=\frac{1}{2}Iw^{2}\\ I=\frac{2E}{w^{2} }\\ I=\frac{2(4.1*10^{6}) }{(1465.3)^{2} }\\ I=3.82 kgm^{2}$