Aflywheel of j = 50 kg-m2 initially standing still is subjected to a constant torque. if the angular velocity reaches 20 hz in 5 s, find the torque given to the flywheel.

Explanation:

given,

J = 50 kg-m²

frequency, f = 20 Hz

time ,t = 5 s

we know,

angular velocity = 2 π f

ω = 2 π x 20

ω = 125.66 rad/s

now, angular acceleration calculation

   α = 25.13 rad/s²

Torque given to the flywheel.

Torque of the given  flywheel is equal to

if the person is shown to have +90n, then ans is -10n.

if the person is shown to have -90n, then ans is +10n.

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.