Question

two forces whose magnitude are in ratio 3:5 give a resultant of 35N if the angle of inclination between the forces is 60° find the magnitude of forces

Answer 1

given

F1/F2 = 3/5

F2 = 5/3(F1) _____(1)

R = 35 N

@ = 60°

by parallelogram law of vector addition we have

R = ✓[(F1)^2 + (F2)^2 + 2|F1|•|F2|•cos@
35 = ✓[(F1)^2 + 25/9(F1)^2+ 10/3(F1)^2•cos60

35 = F(1)•√[1+25/9+10/3×1/2]

F(1) = 35/2.33
F(1) = 15.021 N

and from eqn (1)

F(2) = 5/3(15.021) = 25.025 N