JEE Main 2021 · PhysicsMultiple choiceSingle correctEasyCalculation

JEE Main 25 July 2021, Shift 2, Physics Q6

Question 6 of 90 in this shift, Physics question 6 of 30, Section A.

A force

\vec{F} = (40\hat{i} + 10\hat{j})

N acts on a body of mass 5 kg. If the body starts from rest, its position vector

\vec{r}

at time

t

=10 s, will be :

(1) $(400\hat{i} + 100\hat{j})$ mOfficial answer
(2) $(100\hat{i} + 400\hat{j})$ m
(3) $(100\hat{i} + 100\hat{j})$ m
(4) $(400\hat{i} + 400\hat{j})$ m

Official answer

Option 1

NTA final key.

Chapter: Laws of Motion
Topic: Newton's Laws of Motion
Idea tested: F=ma for Single Body

Same idea in other shifts

Asked 9× in all

4 Apr 2026, Shift 2 · Q28At $t=0$ , a body of mass 100 g starts moving under the influence of a force $\left(5\hat i+10\hat j\right)$ N. After 2 s its position is…EasySingle correct
7 Apr 2025, Shift 2 · Q28An object with mass 500 g moves along $x$ -axis with speed $v=4\sqrt{x}$ m/s. The force acting on the object is :MediumSingle correct
1 Feb 2024, Shift 2 · Q34A body of mass $4$ kg experiences two forces $\vec{F}_1 = 5\hat{i} + 8\hat{j} + 7\hat{k}$ and…EasySingle correct
8 Apr 2023, Shift 1 · Q36At any instant the velocity of a particle of mass $500\ \mathrm{g}$ is $(2t\hat{i}+3t^2\hat{j})\ \mathrm{ms^{-1}}$ . If the force acting on…EasySingle correct
25 Jun 2022, Shift 1 · Q60A force on an object of mass 100 g is $(10\,\hat{i}+5\hat{j})$ N. The position of that object at t = 2 s is $(a\hat{i}+b\hat{j})$ m after…EasyNumerical value
26 Feb 2021, Shift 1 · Q22A boy pushes a box of mass 2 kg with a force $\vec{F}=\left(20\hat{i}+10\hat{j}\right)$ N on a frictionless surface. If the box was…EasyNumerical value
26 Feb 2021, Shift 2 · Q10Two masses A and B, each of mass M are fixed together by a massless spring. A force acts on the mass B as shown in figure. If the mass A…MediumDiagram basedHas a figure
16 Mar 2021, Shift 2 · Q23A body of mass 2 kg moves under a force of $(2\hat{i}+3\hat{j}+5\hat{k})$ N. It starts from rest and was at the origin initially. After 4…EasyNumerical value

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.