Question

A body moves with constant speed $v$ along the circumference of a circle of radius $r$. If it completes half of the revolution in $t$ seconds, then the magnitude of the average acceleration is :

• A. $0$
• B. $\frac{2v}{t}$
• C. $\frac{v}{t}$
• D. All the above

Answer 1

Answer: (B)

$\frac{2v}{t}$

${\overrightarrow{a}}_{avg}=avg.acc{l}^n=\frac{{\overrightarrow{v}}_2-{\overrightarrow{v}}_1}{t_2-t_1}$

Initial velocity, $v_A=v\hat{i}$

Final velocity, ${\overrightarrow{v}}_B=-v\hat{i}$

${\overrightarrow{a}}_{avg}=\frac{-v-\left(v\right)}{t}=\frac{-2v}{t}or\frac{2v}{t}$