Question

A truck travelling due north at $50km/hr$ turns west and travels at the same speed. What is the change in magnitude of velocity (in $km/hr$)?

• A. $50\sqrt{2}$
• B. $50$
• C. $0$
• D. None of these

Answer 1

Answer: (C)

$0$

There is a change in direction of the velocity vector as it turns but the magnitude remains the same.

$\overrightarrow{V_1}=50\hat{j};\left|\overrightarrow{V_1}\right|=50;\overrightarrow{V_2}=-50\hat{i};\left|\overrightarrow{V_2}\right|=50$
Change in magnitude of velocity $=\left|\overrightarrow{V_1}\right|-\left|\overrightarrow{V_2}\right|=0$