Two forces A and B act at a point O. A=30 N at 60 degree and B= 40 N at 120 degree, relative to x-axis. Calculate the magnitude and direction of the resultant force using the method of perpendicular components.

Answer 1

Fx = 30 cos 60 - 40 cos 60

Fy = 30 sin 60 + 40 sin 60

F = sqrt (Fx^2 + Fy^2)

Tan theta = Fy/Fx

Note - Theta is in quadrant 2 because 40>30
Use 180 - the magnitude of the angle