Question

two forces 80N and 70N act simultaneously at a point.Find the resultant force,if the angle between them is 150°

Answer 1

f₁ =80 N 

f₂ = 70N 

F=√f₁² +f₂²+f₁. f₂ cosΦ

F=√6400+4900+5600cos 150° 

F=√ 11300+5600 . -√3/2 

F =√11300+2800.-√3 

F=10√113-28√3 

F=10√113-(28x1.73) 

F=10√113-48.44 

F=10√64.56 

F=10×8.034 

F 80.34N