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

Options

A. `120^(@)`
B. `60^(@)`
C. `90^(@)`
D. `0^(@)`

Answer

A

Explanation

`P=Q 2N, R=2N`
`R^(2)=P^(2)+Q^(2)=2PQ Cos theta`
`4=4+4+2(4)+Cos theta`
`cos theta=(-4)/(8)=(-1)/(2), theta=120^@`