Question

A body is traversing on the x-y plane with constant speed. At the start of the motion, the particles velocity is $40\hat{i}$ and after 30 sec its velocity becomes $40\hat{j}$. Find the average acceleration.

• A. 0 as speed constant
• B. $\frac{4}{3}\hat{i}+\frac{4}{3}\hat{j}$
• C. $\frac{4}{3}\hat{i}-\frac{4}{3}\hat{j}$
• D. $\frac{-4}{3}\hat{i}+\frac{4}{3}\hat{j}$

Answer 1

The correct option is D

$\frac{-4}{3}\hat{i}+\frac{4}{3}\hat{j}$

Average acceleration = $\frac{changeinvelocity}{timetaken}$= $\frac{v_f-v_i}{t}=\frac{40\hat{j}-40\hat{i}}{30}$