Question

An object is acted upon by two forces 20N each .The angle between the forces is 120 degrees.The resultant force on the object has the magnitude of what

Answer 1

$F_{res}=\sqrt{F_1^2+F_2^2+2F_1F_2cos\alpha},$

$F_1=F_2=F=20~N,$

$F_{res}=\sqrt{F^2+F^2-F^2}=F=20~N.$