Question

The resultant of the two forces 3N and2N at an angle θ is doubled when first force in increased to 6N. Find θ?

Answer 1

Answer: 120°

Explanation:

The resultant of two forces can be calculated by:

F = √(F1²+F2²+2(F1)(F2)cos(angle between the applied forces))

Where,

F= the resultant force

F1= applied first force

F2= applied second force

Now, in the first scenario, F1= 3N and F2=2N, hence there resultant for Angle 'A' would be

F=√(3²+2²+2(3)(2)cos(A)) calling it--(i)

And in second scenario, the resultant is made two times when F1 changes to 6N,

2F = √(6²+2²+2(6)(2)cos(A)) calling it --(ii)

NOTE: For change in forces, the angle kept is same.

Now divide (ii) by (i) and do some simple maths to find A that is the required angle.