question_answer

The resultant of two forces acting at an angle of \[120{}^\circ \] is 10 kg-wt and is perpendicular to one of the forces. That force is

A)  10\[\sqrt{3}\] kg-wt     

B)  20\[\sqrt{3}\] kg-wt

C)  10 kg-wt       

D)  \[\frac{10}{\sqrt{3}}\] kg-wt

Correct Answer: D

Solution :

Here,        \[\tan {{30}^{o}}=\frac{1}{\sqrt{3}}\] \[\frac{1}{\sqrt{3}}=\frac{x}{10}\] \[x=\frac{10}{\sqrt{3}}kg-wt\]