JEE Mains · Physics · STD 11 - System of particles and rotational motion
- JEE Mains 2022
- Easy
- MCQ
If force \(\vec{F}=3 \hat{i}+4 \hat{j}-2 \hat{k}\) acts on a particle having position vector \(2 \hat{i}+\hat{j}+2 \hat{k}\) then, the torque about the origin will be
Pick an option to check your answer.
Answer & Solution
Correct Answer
(B) \(-10 \hat{ i }+10 \hat{ j }+5 \hat{ k }\)
Step-by-step Solution
Detailed explanation
\(\vec{\tau}=\vec{r} \times \vec{F}\)
\(=\left|\begin{array}{ccc}\hat{i} & \hat{j} & \hat{k} \\ 2 & 1 & 2 \\ 3 & 4 & -2\end{array}\right|\)
\(=\hat{\hat{i}}(-2-8)-\hat{ j }(-4-6)+\hat{ k }(8-3)\)
\(=-10 \hat{ i }+10 \hat{ j }+5 \hat{ k }\)
More questions from Physics
- A solid metallic cube having total surface area \(24\;m ^{2}\) is uniformly heated. If its temperature is increased by \(10\,^{\circ} C\), calculate the increase in volume of the cube \(\left(\right.\) Given \(\left.: \alpha=5.0 \times 10^{-4}{ }^{\circ} C ^{-1}\right)\)JEE Mains 2022 Medium
- A passenger sitting in a train A moving at \(90\,km / h\) observes another train \(B\) moving in the opposite direction for \(8\,s\). If the velocity of the train \(B\) is \(54\,km / h\), then length of train \(B\) is \(..........\,m\)JEE Mains 2023 Medium
- The moment of inertia of a circular ring of mass \(M\) and diameter r about a tangential axis lying in the plane of the ring is :JEE Mains 2025 Easy
- A mosquito is moving with a velocity \(\overrightarrow{ v }=0.5 t ^{2} \hat{ i }+3 t \hat{ j }+9 \hat{ k }\, m / s\) and accelerating in uniform conditions. What will be the direction of mosquito after \(2 \,s\) ?JEE Mains 2021 Hard
- The speed of sound in oxygen at \(S.T.P. \)will be approximately _______. (Given, \(\mathrm{R}=8.3 \mathrm{JK}^{-1}, \gamma=1.4\) )JEE Mains 2024 Easy
- A solid sphere of radius \(R\) carries a charge \((Q+q)\) distributed uniformly over its volume. A very small point like piece of it of mass \(m\) gets detached from the bottom of the sphere and falls down vertically under gravity. This piece carries charge \(q.\) If it acquires a speed \(v\) when it has fallen through a vertical height \(y\) (see figure), then : (assume the remaining portion to be spherical).
JEE Mains 2020 Hard
More PYQs from JEE Mains
- Find the equivalent resistance between two ends of the following circuit
JEE Mains 2025 Easy - A given object takes \(n\) times the time to slide down \(45^{\circ}\) rough inclined plane as it takes the time to slide down an identical perfectly smooth \(45^{\circ}\) inclined plane. The coefficient of kinetic friction between the object and the surface of inclined plane is _______.JEE Mains 2024 Hard
- A monkey of mass \(50\,kg\) climbs on a rope which can withstand the tension \((T)\) of \(350\,N\). If monkey initially climbs down with an acceleration of \(4\,m / s ^{2}\) and then climbs up with an acceleration of \(5\,m / s ^{2}\). Choose the correct option \(\left( g =10\,m / s ^{2}\right)\)JEE Mains 2022 Medium