Question

A flywheel has mean kinetic energy of rotation equal to 100 N-m. If the coefficient of fluctuation of speed is 0.012. What is the maximum fluctuation of energy flywheel?

• A. 1.2 N-m
• B. 2.4 N-m
• C. 3.6 N-m
• D. 4.8 N-m

Answer 1

The correct option is B 2.4 N-m

Maximum flutuation of energyin flywheen is given by

$\Delta E_{max}=\frac{1}{2}I({\omega }_{max}^2-{\omega }_{min}^2)$

$=I\left(\frac{{\omega }_{max}+{\omega }_{min}}{2}\right)({\omega }_{max}-{\omega }_{min})$

$\Delta E=I{\omega }_{mean}\times \Delta \omega =I{\omega }_{mean}^2\times \frac{\Delta \omega }{{\omega }_{mean}}$

$=I{\omega }^2\times C_s$

$E=\frac{1}{2}I{\omega }^2$

$\Delta E=2E\times C_s$

$=2\times 100\times 0.012=2.4N-m$