Question

Two intersecting straight lines move with speeds $3m/s$ and $4m/s$ parallel to themself. If angle between the lines is ${90}^o$ then speed of intersection point is -

• A. $5m/s$
• B. $3m/s$
• C. $4m/s$
• D. None

Answer 1

The correct option is A $5m/s$

Velocity of the intersecting point $\overrightarrow{V_o}=\overrightarrow{V_x}+\overrightarrow{V_y}=3\hat{i}+4\hat{j}$

$\therefore$ $|\overrightarrow{V_o}|=\sqrt{V_x^2+V_y^2}=\sqrt{3^2+4^2}=\sqrt{25}$

$⟹$ $V_o=5m/s$