Three forces act on an object. A 4 N force acts due east and a 3 N force acts due north. If the net force on the object is zero, what is the magnitude of the third force?

Answer 1

well it is 4 N WEST and 3 N SOUTH
5 = sqrt (4^2 + 3^2)
so magnitude of 5 N

Now how far West of South
tan angle = 4/3
angle = 53.1 deg W of S
so
53.1 + 180 = 233.1 Clockwise from North (Compass direction, not math)

Answer 2

F1 + F2 = 4 + 3i = 5N[36.9o] N. of E. = 36.9o CCW.
The magnitude of F3 = F1 + F2 but 180o out phase:
F3 = 5N[36.9o] S. of W. = 216.9o CCW.

Answer 3

Two forces 12N and 13N act on a body of mass 5kilogram calculate the acceleration of the body