Question

A string is wrapped over a solid cylinder of mass $5kg$ and radius $1m$. When $40N$ force is applied tangentially on cylinder as shown, determine its angular acceleration about centre in $rad{s}^{-2}$(floor is smooth).

• A. $16$
• B. $8$
• C. $24$
• D. $4$

Answer 1

The correct option is A $16$

Torque Equation
$Fr=I\alpha$
$I$ is Moment of Inertia of rod about centre of cylinder
$\alpha$ is angular acceleration
$Fr=\frac{M{r}^2}{2}\alpha$
$\frac{2F}{Mr}=\alpha$
$\frac{80}{5}=\alpha =16rad{s}^{-2}$