Question

$12$ coplanar non collinear forces (all of equal magnitude) maintain a body in equilibrium, then the angle between any two adjacent forces is:

• A. ${15}^{\circ }$
• B. ${30}^{\circ }$
• C. ${45}^{\circ }$
• D. ${60}^{\circ }$

Answer 1

Answer: (B)

${30}^{\circ }$

According to polygon law of vector addition, the 11 forces will be the sides of polygon in same order in direction and 1 forces will represent the resultant which is a side in opposite order of the polygon. Total angle enclosed by polygon is ${360}^o$. So, the required angle $=\frac{{360}^o}{12}={30}^o$