Question

The radius of a flywheel is $10cm$. It is rotated at the rate of $25rad{s}^{-2}$. When a constant force $40N$ is applied on the rim of wheel along its tangent. The moment of inertia of wheel is:

• A. $0.01kg{m}^2$
• B. $0.1kg{m}^2$
• C. $0.16kg{m}^2$
• D. $1.6kg{m}^2$

Answer 1

The correct option is C $0.16kg{m}^2$

Torque on wheel $=F\times R$ as it is applied at tangent
$=40\times 0.1$
$=4Nm$
Torque $\tau =I\alpha$
$4=I\times 25$
$\Rightarrow I=\frac{4}{25}=0.16kg{m}^2$