Question

 If two forces are acting at a point such that the magnitude each force is 2 N and the magnitude of their resultant is also 2 N, then the angle between two forces is


120 degree

60 degree

90 degree

0 degree

​

Answer 1

Given:

Two forces are acting at a point such that the magnitude each force is 2 N and the magnitude of their resultant is also 2 N.

To find:

Angle between them?

Calculation:

• Let the angle be $\theta$.

$R = \sqrt{ {A}^{2} + {B}^{2} + 2AB \cos( \theta) }$

$\implies 2 = \sqrt{ {2}^{2} + {2}^{2} + 2.2.2\cos( \theta) }$

$\implies 2 = \sqrt{ 8+ 8\cos( \theta) }$

$\implies 4= 8+ 8\cos( \theta)$

$\implies 8\cos( \theta) = - 4$

$\implies \cos( \theta) = - 0.5$

$\implies \theta = {120}^{ \circ}$

So, the angle is 120°.