Question

A car moves in a circular path with constant speed $v$. What is the magnitude of change in velocity after the radius vector has described an angle of ${60}^{\circ }$ ?

• A. $2v$
• B. $v$
• C. $\sqrt{3}v$
• D. $0$

Answer 1

Answer: (B)

$v$

Change in velocity, $\Delta \overrightarrow{v}=|\overrightarrow{v_f}-\overrightarrow{v_i}|$
The angle between $-\overrightarrow{v_i}$ and $\overrightarrow{v_f}$ is $=\sqrt{v^2+v^2+2vvcos{120}^{\circ }}=\sqrt{v^2}=v$