Question

A flywheel of mass 35.0 kg and diameter 60.0 cm spins at 420 rpm when it experiences a sudden power loss. The flywheel slows due to friction in its bearings during the 19.0 s the power is off. The flywheel makes 90 complete revolutions during the power failure. 1) At what rate is the flywheel spinning when the power comes back on? (Express your answer to two significant figures.)

Answer 1

`\omega _(f)=15.51rad/sec`

Step-by-step explanation:

We have have given that mass of the flywheel m = 35 kg

Diameter = 60 cm

Time t = 19 sec

Flywheel completes 90 complete revolutions

So
`\Theta =90* 2* \pi =565.2radian`

Initial angular speed
`\omega _(i)=420rpm =43.98rad/sec`

We know that angular displacement is given by

`\Theta =(\omega _(i)+\omega _(f))/(2)* t`

`565.2 =(43.98+\omega _(f))/(2)* 19`

`\omega _(f)=15.51rad/sec`