Forces of 300 pounds and 400 pounds act on a particle in a p

Forces of 30.0 pounds and 40.0 pounds act on a particle in a plane at an angle of 120degree with respect to each other. To the nearest tenth of a pound, find the magnitude of the resultant of this force.

Solution

Resultant force = (30^2 + 40^2 + 2×30×40×cos120)

= (900+1600-1200)

= 1300

= 1013

= 36.1 pounds