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A 4 kg mass moves under the influence of a force F= (4 t^3 i-3 t j ) N where t is the time in second. If mass starts from origin at t=0, the velocity…

JEE Main 2026 — Physics Mechanics

2026mcqmedium

A 4 kg mass moves under the influence of a force F⃗=(4t3i^−3tj^)N\vec{F}=\left(4 t^{3} \hat{i}-3 t \hat{j}\right) \mathrm{N}F=(4t3i^−3tj^​)N where ttt is the time in second. If mass starts from origin at t=0t=0t=0, the velocity and position after t=2 st=2 \mathrm{~s}t=2 s will be:

Official previous-year question

Held on 21 Jan 2026 · Verified 6 Jul 2026.

Options

  1. A

    v⃗=4i^−32j^r⃗=65i^−j^\vec{v}=4 \hat{i}-\frac{3}{2} \hat{j} \quad \vec{r}=\frac{6}{5} \hat{i}-\hat{j}v=4i^−23​j^​r=56​i^−j^​

  2. B

    v⃗=3i^+32j^r⃗=65i^+j^\vec{v}=3 \hat{i}+\frac{3}{2} \hat{j} \quad \vec{r}=\frac{6}{5} \hat{i}+\hat{j}v=3i^+23​j^​r=56​i^+j^​

  3. C

    v⃗=4i^−32j^r⃗=85i^−j^\vec{v}=4 \hat{i}-\frac{3}{2} \hat{j} \quad \vec{r}=\frac{8}{5} \hat{i}-\hat{j}v=4i^−23​j^​r=58​i^−j^​

  4. D

    v⃗=4i^+52j^r⃗=85i^+2j^\vec{v}=4 \hat{i}+\frac{5}{2} \hat{j} \quad \vec{r}=\frac{8}{5} \hat{i}+2 \hat{j}v=4i^+25​j^​r=58​i^+2j^​

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