An initially installed flywheel can store 10⁶ J of kinetic energy when rotating at 300 rad/s. It is replaced by another flywheel of the same size but made of a stronger material. If its mass is the same as that of the original, and it is now capable of achieving a rotational speed of 600 rad/s, what maximum energy can be stored?

Question

Quizplus · Accepted Answer

The kinetic energy stored in a flywheel is given by:$$E = \frac{1}{2} I \omega^2$$where:* E is the kinetic energy in joules* I is the moment of inertia in kg-m^2* ω is the angular velocity in radians per secondIf the mass and size of the flywheel are the same, then the moment of inertia will be the same. Therefore, the kinetic energy stored will be proportional to the square of the angular velocity.If the angular velocity is doubled, then the kinetic energy will be quadrupled. Therefore, the maximum energy that can be stored in the new flywheel is:$$E = 4 	imes 10^6 J = 40 	imes 10^5 J$$

An Initially Installed Flywheel Can Store 106 J of Kinetic

An Initially Installed Flywheel Can Store 10⁶ J of Kinetic