One of the following forces is double and the other resultant is equal to the greater force. The angle between them is

Options

A. `cos^(-1)(1//2)`
B. `cos^(-1)(-1//2)`
C. `cos^(-1)(1//4)`
D. `cos^(-1)(-1//4)`

Answer

D

Explanation

`P = x , Q = 2x , R = 2x`
`R^(2) = P^(2) + Q^(2) + 2 PQ cos theta`
`(2x)^(2) = (x)^(2) + (2x)^(2) + 2 . X . 2x cos theta`
`theta = cos ^(-1) (-1//4)`