The greatest and least resultant of two forces acting at a point are 16N and 4N. If they are acting at an angle 120 degrees with one another their resultant is

A. root 38N , B.root 76N, C.root 19N, D.none

4 answers

The two forces clearly have magnitudes 6 and 10.

So, use the law of cosines to get

r^2 = 100+36-120(-1/2) = 196
r = 14
F1+F2=16 ,F1-F2=4 so F1=10,F2=6 r=root over 10^2+6^2+2×10×6×1÷2 r=root 100+36+60=root 100+96 r =root 196 =14
Root 76N
✓76