A flywheel is a solid disk that rotates about an axis that is perpendicular to t

Question

A flywheel is a solid disk that rotates about an axis that is perpendicular to the disk at its center. Rotating flywheels provide a means for storing energy in the form of rotational kinetic energy and are being considered as a possible alternative to batteries in electric cars. The gasoline burned in a 360-mile trip in a typical midsize car produces about 1.90 109 J of energy. How fast would a 11-kg flywheel with a radius of 0.31 m have to rotate to store this much energy? Give your answer in rev/min.

Explanation / Answer

Here ,

energy produced by gasoline in the trip

E = 1.9 *10^9 J

mass of flywheel , m = 11 Kg

radius , r = 0.31 m

let the angular speed is w

Using conservation of energy

0.5 * I * w^2 = energy stored

0.5 * 0.5 * m * r^2 * w^2 = 1.90 *10^9

0.25 * 11 * 0.31^2 * w^2 = 1.90 *10^9

solving for w

w = 84791 rad/s = 84791 * 2pi/60 rev/min

w = 8877.62 rev/min

the angular speed of the flywheel needed is 8877.62 rev/min

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.