Physics · Newton's Laws of Motion

JEE Main 2025 — 8 April, Evening Shift — Question 54

A body of mass 2 kg moving with velocity of $\vec{v}_{\text {in }}=3 \hat{i}+4 \hat{j} \mathrm{~ms}^{-1}$ enters into a constant force field of 6 N directed along positive z -axis. If the body remains in the field for a period of $\frac{5}{3}$ seconds, then velocity of the body when it emerges from force field is :

Option A:
$3 \hat{i}+4 \hat{j}+5 \hat{k}$
Correct
Option B:
$3 \hat{i}+4 \hat{j}-5 \hat{k}$
Option C:
$4 \hat{i}+3 \hat{j}+5 \hat{k}$
Option D:
$3 \hat{i}+4 \hat{j}+\sqrt{5} \hat{k}$

Answer: A

Step-by-step solution

$\vec{F} \cdot t=m\left(\vec{v}_{2}-\vec{v}_{1}\right)$

\begin{aligned} & \frac{6}{2} \times \frac{5}{3} \hat{k}=\vec{v}_{2}-\vec{v}_{1} & \vec{v}_{2}=\vec{v}_{1}+5 \hat{k}=3 \hat{i}+4 \hat{j}+5 \hat{k} \end{aligned}

Answer key and solution verified before publishing.

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Exam: JEE Main 2025
Paper: 8 April, Evening Shift
Subject: Physics
Chapter: Newton's Laws of Motion
Topic: Application of NLM and Impulse