Q. Two forces $\overrightarrow{F_{1}}\ $ and $\overrightarrow{F_{2}}$ are acting at right angles to each other. Then their resultant is
A) $F_{1} + F_{2}$
B) $\sqrt{F_{1}^{2} + F_{2}^{2}}$
C) $\sqrt{F_{1}^{2} - F_{2}^{2}}$
D) $\frac{F_{1} + F_{2}}{2}$
Explanation
(b) $F^{2} = F_{1}^{2} + F_{2}^{2} + 2F_{1}F_{2}\cos 90{^\circ}$
or $F^{2} = F_{1}^{2} + F_{2}^{2} \Rightarrow F = \sqrt{F_{1}^{2} + F_{2}^{2}}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.