Question

A particle $A$ is moving with a speed of $20\text{m/s}$ towards right and another particle $B$ is moving at a speed of $5\text{m/s}$ towards right. Find their velocity of approach.

• A. $5\text{m/s}$
• B. $15\text{m/s}$
• C. $20\text{m/s}$
• D. $25\text{m/s}$

Answer 1

The correct option is B $15\text{m/s}$

Velocity of particle, $V_A=+20$
Velocity of particle, $V_B=+5$
Velocity of approach,
$V_{AB}=V_A-V_B$
$V_{AB}=20-(+5)=15\text{m/s}$
Hence the approach velocity, $V_{\text{app}}=\left|V_{AB}\right|=15\text{m/s}$