Q63 / 90 · KVPY 2013 (SB/SX) · Physics
A wheel of radius $R$ with an axle of radius $R / 2$ is shown in the figure and is free to rotate about a frictionless axis through its centre and perpendicular to the page. Three forces $(F, F, 2 F)$ are exerted tangentially to the repective rims as shown in the figure.
The magnitude of the net torque acting on the system is nearly
The magnitude of the net torque acting on the system is nearly
- Correct answerA$3.5 \mathrm{FR}$
- B$3.2 \mathrm{FR}$
- C$2.5 \mathrm{FR}$
- D$1.5 \mathrm{FR}$
Solution
$\tau_{\text {Net }}=F\left(\frac{R}{2}\right)+F R+2 F R=3.5 \mathrm{FR}$
Hence, the correct answer is option: 'A'.