Question

two equal forces have their resultant equal to either what is inclination between them .

Answer 1

Answer:

let us consider two forces F & F'.

as per the magnitude of resultant of these two forces are equal to either

hence. F = F' = R

let the angle between F & F' is theta.

as per parallelogram law of vector addition,

R = under root F^2+F'^2+2FF'cos theta

= under root R^2+R^2+2R-R cos theta

= under root 2R^2+2R^2 cos theta

= under root 2R^2(1+cos theta)

squaring both sides we get R^2=2R^2(1+ cos theta)

=1/2+1+ cos theta

= cos theta = -1/2

theta = 120°