Question

magnitude of the resultant of two forces of the same magnitude equal to the magnitude of them. then the angle between those vectors is
A.0 degrees B 60 degrees C.120.degrees D.90degrees

Answer 1

magnitudes of forces = P and P.
let Ф be the angle between them.

magnitude of Resultant = P²  = P² + P² + 2 P P Cos Ф

       =>  CosФ = -1/2
       =>  Ф = 120 deg or  2π/3