A flywheel of moment of inertia 5 kg meter squared is rotating at 10 radians per second. A constant retarding torque is applied to bring it to rest in 5 seconds. What is the magnitude of the torque?

B. 10 Nm — The torque is equal to the rate of change of angular momentum. Since the torque is constant, it is equal to the moment of inertia multiplied by the angular acceleration.

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$A flywheel of moment of inertia 5 kg m^{2} is rotating at 10 rad/s . A constant retarding torque is applied to bring it to rest in 5 s . What is the magnitude of the torque?$

A. $5 Nm$
B. $10 Nm$
C. $25 Nm$
D. $2 Nm$

Show correct answer & step-by-step solution

Correct answer: B — $10 Nm$

Solution

Torque τ = I α . The angular acceleration α = Δ ω /Δ t = (0 - 10) /5 = - 2 rad/s^{2} . Thus, magnitude τ = 5 \times 2 = 10 Nm .

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A flywheel of moment of inertia 5 kg m2 is rotating at 10 rad/s. A constant retarding torque is applied to bring it to rest in 5 s. What is the magnitude of the torque?

Solution

Attempt this question & track your score

More Rotational Motion practice questions

$A flywheel of moment of inertia 5 kg m^{2} is rotating at 10 rad/s . A constant retarding torque is applied to bring it to rest in 5 s . What is the magnitude of the torque?$