Question

The total torque about pivot A provided by the forces shown in figure, for L=3.0m is

Answer 1

Moment of force about pivot A (80 N force) 

=80×3/2×sin30^o

= 60 N-m (anticlockwise) Moment of force about pivot A (70 N force) 

=70×3×sin30^o=70×3×1/2

 = 10⁵ N-m (anticlockwise) Moment of force about pivot A (60 N force) 

=60×3/2×sin90^o

 = 90 N-m (clockwise) Moment of force about pivot A (90 N force) 

=90×0×sin60^o=0

 Moment of force about pivot A (50 N) 

=50×3×sin180^o=0

 The total torque about pivot A 

T=(60+105−90)

 = 75 N-m