Three forces N, 14N and 16N acting on a particle keep it in equilibrium. Find the angle between the forces 10N and 16N.
Explanation
If we let (beta) be the angle between the forces 10N and 16N,
then (beta) = (180(^o) – (theta))
Applying the cosine rule; cos(theta) = (frac{10^2 + 16^2 – 14^2}{2 times 10 times 16}) = 0.5
If (theta) = cos(^{-1})(0.5) = 60(^o)
(beta) = 180(^o) – 60(^o) = 120(^o)