Torque MCQ - Practice Questions with Answers

• The vector product of the Force vector and position vector is known as torque.
• - $\overrightarrow{\tau }=\overrightarrow{r}\times \underset{F}{\overrightarrow{F}}$
• - Its direction is always perpendicular to the plane containing vectors r and F and with the help of the right-hand screw rule we can find it.
• - The magnitude of torque is calculated by using either
• - $\tau =r_{1}F$ or $\tau =r\cdot F_1$
• $r_1=$ perpendicular distance from the origin to the line of force.
• $F_1=$ component of force perpendicular to line joining force.
• - $\tau =r.F\cdot \sin \varphi$
• Where $\varphi$ is the angle between vector r and F
• - ${\tau }_{\text{max }}=r.F($ when $\varphi ={90}^0)$
• - ${\tau }_{\text{min }}=0(when\varphi =0^0)$

•  If a pivoted, hinged body tends to rotate due to an applied force, then it is said that torque is acted on the body by force.

Example-

In the rotation of a hinged door when we apply torque with the help of force F.

- SI Unit- Newton-metre
- Dimension- $M{L}^2{T}^{-2}$
- If a body is acted upon by more than one force, then we get the resultant torque by doing the Vector sum of each torque.

$$\tau ={\tau }_1+{\tau }_2+{\tau }_3\cdots \cdots$$

- Just like force is the cause of translatory motion similarly Torque is the cause of rotatory motion.