Two equal vector have a resultant equal to either of them, then the angle between them will be:

Options

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

Answer

D

Explanation

Let `F_(1)= F_(2) = F` be forces them , `F_(2)= 2F`
`F_(R)= sqrt(F_(1)^(2) + F_(2)^(2) + 2F_(1)F_(2) cos theta)`
`(2F)^(2) = 2F^(2)+ 2F^(2) costheta `
`cos theta =1`
`theta = 0^(@)`