Topic: Theory of Machines
A circular solid disc of uniform thickness 20mm, radius 400 mm and mass 10 kg, is used as a flywheel. If it rotates at 300 rpm, the kinetic energy of the flywheel, in Joules is
- A. 395
- B. 790
- C. 1580
- D. 3160
Answer: A. 395
Explanation: KE = (1/2)*I*omega². I = (m*r²)/2 = (10 * 0.4^2) / 2 = 0.8 kg-m². omega = 2*pi*300/60 = 10*pi rad/s. KE = 0.5 * 0.8 * (10*pi)^2 = 40 * pi² = 394.78 J, approximately 395 J.