Question

A particles velocity changes from $(2\hat{i}+3\hat{j})m/s$ to $(2\hat{i}-3\hat{j})m/s$ in $2$ sec. The acceleration is

• A. $-(\hat{i}+5\hat{j})$
• B. $\frac{(\hat{i}+5\hat{j})}{2}$
• C. zero
• D. $-3\hat{j}$

Answer 1

Answer: (D)

$-3\hat{j}$

Acceleration of particle $\overrightarrow{a}=\frac{\overrightarrow{v}-\overrightarrow{u}}{t}$

Or $\overrightarrow{a}=\frac{(2\hat{i}-3\hat{j})-(2\hat{i}+3\hat{j})}{2}=-3\hat{j}$