Question

A body is moving in a circle at a uniform speed n. What is the magnitude of the change in velocity when the radius vector describes an angle q ?

• A. ncosq
• B. 2ncos$\left( \frac{\theta}{2} \right)$
• C. n sin q
• D. 2n sin $\left( \frac{\theta}{2} \right)$

Answer 1

Answer: (D)

2n sin $\left( \frac{\theta}{2} \right)$

Answer 2

$\Delta\overset{\rightarrow}{v}$ = ${\overset{\rightarrow}{v}}_{f}$ – ${\overset{\rightarrow}{v}}_{i}$| D$\overset{\rightarrow}{v}$| = $\sqrt{v^{2} + v^{2} - 2v^{2}\cos\theta}$

[Q v_f = v_i]

= 2v sin $\frac{\theta}{2}$