Question

1. Two forces of 20 N each are acting at a point.
If the forces make an angle of 120° between
them, then what will be the resultant force?
(1) 20 N
(2) 40 N.
(3) 2002 N (4) 40/2N​

Answer 1

we know that

R = sqrt(f1^2 + f2^2 + 2f1f2cos@)

R = sqrt(400+400+2*400cos120)

since cos (90 + 30) = - sun30 = -1/2

R = sqrt (800 - 400)

R = 20N