JEE Main 2020 · PhysicsMultiple choiceSingle correctEasyConceptual

JEE Main 8 January 2020, Shift 2, Physics Q2

Question 2 of 75 in this shift, Physics question 2 of 25, Section A.

A particle moves such that its position vector

\vec{r}(t)=\cos\omega t\,\hat{i}+\sin\omega t\,\hat{j}

where

\omega

is a constant and t is time. Then which of the following statements is true for the velocity

\vec{v}(t)

and acceleration

\vec{a}(t)

of the particle :

(1) $\vec{v}$ and $\vec{a}$ both are parallel to $\vec{r}$
(2) $\vec{v}$ and $\vec{a}$ both are perpendicular to $\vec{r}$
(3) $\vec{v}$ is perpendicular to $\vec{r}$ and $\vec{a}$ is directed towards the originOfficial answer
(4) $\vec{v}$ is perpendicular to $\vec{r}$ and $\vec{a}$ is directed away from the origin

Official answer

Option 3

NTA final key (Jan 2020).

Chapter: Motion in a Plane
Topic: Circular Motion
Idea tested: Vector Cross Products in Circular Motion

Same topic in other shifts

All Circular Motion questions

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.