Answer:
120°
Explanation:
Given forces with magnitude F and F
Applying the parallelogram law of vector
Where resultant is given as :
R = √(A^2 + B^2 + 2ABCos Ф
WHERE A and B are two forces with angle Ф
F =√(F^2 + F^2 + 2F * F Cos Ф
Square both sides
F^2 = F^2 + F^2 + 2F^2 CosФ
F^2 - 2F^2 = 2F^2 CosФ
- F^2 = 2F^2 Cos Ф
Divide both sides by 2F^2
- 1 / 2 = CosФ
Cosine(theta) = - 1/2
Ф = cosi^-1 (-1/2)
Ф = 120°
