Question

Delivery trucks that operate by making use of energy stored in a rotating flywheel have been used in Europe. The trucks are charged by using an electric motor to get the flywheel up to its top speed of 940 rad/s. One such flywheel is a solid homogenous cylinder, rotating about its central axis, with a mass of 630 kg and a radius of 1.35 m. What is the kinetic energy of the flywheel after charging?

Answer 1

Answer:

KE = 2.535 x 10⁷ Joules

Explanation:

given,

angular speed of the fly wheel = 940 rad/s

mass of the cylinder = 630 Kg

radius = 1.35 m

KE of flywheel = ?

moment of inertia of the cylinder

$I = \dfrac{1}{2}mr^2$

 =$\dfrac{1}{2}\times 630\times 1.35^2$

 = 574 kg m²

kinetic energy of the fly wheel

$KE = \dfrac{1}{2}I\omega^2$

$KE =\dfrac{1}{2}\times 574\times 940^2$

KE = 2.535 x 10⁷ Joules

the kinetic energy of the flywheel is equal to KE = 2.535 x 10⁷ Joules