The position vector of a particle related to time t is given by r = (10ti + 15t²j + 7k) m The direction of net force experienced by the particle is: (a) Positive x - axis (b) Positive y - axis (c) Positive z - axis (d) In x-y plane

Answer: (b). v = dr/dt = 10i + 30tj a = dv/dt = 30j, so F = ma is along +j. So the answer is (b) positive y -axis.

The position vector of a particle related to time t is given by r =… | JEE Main 2023 (15 Apr, Shift 1)

Q13JEE Main 2023 · 15 APR · SHIFT 1Easy

Inertia, First & Second Laws

The position vector of a particle related to time $t$ is given by

$\vec{r} = \left(10t\hat{i} + 15t^2\hat{j} + 7\hat{k}\right)\text{ m}$

The direction of net force experienced by the particle is:

Show answer and solution

Answer: (b)

$\vec{v} = \frac{d\vec{r}}{dt} = 10\hat{i} + 30t\hat{j}$
$\vec{a} = \frac{d\vec{v}}{dt} = 30\hat{j}$ , so $\vec{F} = m\vec{a}$ is along $+\hat{j}$ .
So the answer is (b) positive $y$ -axis.

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