Question

A particle is moving east-wards with a velocity of 5 m/sec. In 10 seconds its velocity changes to 5 m/sec north-wards. The average acceleration during this time is -

Answer 1

Initial velocity $u=5\hat{i}$

Final velocity $v=5\hat{j}$

Change in velocity $\Delta v=v-u=5(\hat{j}-\hat{i})$

Average acceleration $a=\frac{\Delta v}{\Delta t}=\frac{5(\hat{j}-\hat{i})}{10}=\frac{\hat{j}-\hat{i}}{2}$

Magnitude $|a|=\frac{1}{2}\times \sqrt{1^2+1^2}=\frac{1}{\sqrt{2}}m/s^2$