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 310 mile trip in a typical midsize car produces about 1.20 109 J of energy. How fast would a 10 kg flywheel with a radius of 0.30 m have to rotate in order to store this much energy? Give your answer in rev/min. give exact answer without changing the numbers!!!

Explanation / Answer

Rotational KE = .5Iw^2

I for a disk is .5mr^2

I = (.5)(10)(.3)^2 = .45 kgm^2

1.20 X 10^9 = (.5)(.45)(w^2)

w = 73030 rad/s

Convert to rev/min

73030 times 1/2pi times 60sec/min

6.97 X 10^5 rev/min

If you want the actual number, that is 697382 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.