Question

A particle is moving along a circular path of radius 5 m and uniform speed 5 $m{s}^{-1}$. What will be the average acceleration when the particle completes half revolution?

• A. $10\pi m{s}^{-2}$
• B. $10/\pi m{s}^{-2}$
• C. $10m{s}^{-2}$
• D. zero

Answer 1

Answer: (B)

$10/\pi m{s}^{-2}$

average acceleration $=\overrightarrow{a}=\frac{\Delta v}{t}=\frac{v_2-v_1}{t}=\frac{(-5\hat{i})-\left(5\hat{i}\right)}{t}=\frac{-10\hat{i}}{t}$

and $t=\frac{5\pi }{5}=\pi$

$\Rightarrow \overrightarrow{a}=\frac{-10\hat{i}}{\pi }m{s}^{-2}\Rightarrow \left|a\right|=\frac{10}{\pi }m{s}^{-2}$