Find the resultant of two forces of 4N and 5N if they are incline perpendicular to each other

Answer 1

x force = 4
y force = 5
|F|^2 = 16 + 25
|F| = sqrt ( 41 ) = 6.4 Newtons
tan theta= 5/4 = 1.25
theta = 51.3 degrees above x axis