Question

A particle is moving eastwards with a velocity $5m/s$, changes its direction northwards in $10$ seconds and moves with the same magnitude of the velocity. The average acceleration is ____.

• A. $\frac{1}{\sqrt{2}}m/s^2$ towards S-W
• B. $\frac{1}{\sqrt{2}}m/s^2$ towards N-E
• C. $\frac{1}{\sqrt{2}}m/s^2$ towards S-E
• D. $\frac{1}{\sqrt{2}}m/s^2$ towards N-W

Answer 1

The correct option is D $\frac{1}{\sqrt{2}}m/s^2$ towards N-W

Change in velocity $=$ $5m/s$ along east and north $=5m/s$ magnitude
Average change in velocity $=$ $5\sqrt{2}$
Average acceleration $=-5i+5j$
Avg. acceleration $=$ avg. change in velocity/time $=\frac{5\sqrt{2}}{10}=\frac{1}{\sqrt{2}}m/s^2$ towards north west.