JEE PYQ: Laws Of Motion Question 5
Question 5 - 2021 | 16 Mar Shift 2] (Numerical)
A 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 s, its new coordinates are $(8, b, 20)$. The value of $b$ is ____.
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Answer: 12
Solution
$\vec{a} = \frac{\vec{F}}{m} = \hat{i} + 1.5\hat{j} + 2.5\hat{k}$. $\vec{r} = \frac{1}{2}\vec{a}t^2 = 8\hat{i} + 12\hat{j} + 20\hat{k}$. So $b = 12$.
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