Question

Determine the net torque (in Nm) acting on a 50.0 g meter stick that has a fulcrum placed at its center of mass (50cm) and a 75g mass attached to the 10 cm mark and a 35g mass attached to the 60 cm mark.

Answer 1

let
m1 = 50.0 g = 0.050 kg
m2 = 75 g = 0.075 kg
m3 = 35 g = 0.035 kg

Net torque about the fulcrum, Tnet = m1*g*0 + m2*g*(0.5 - 0.1) - m2*g*(0.6 - 0.5)

= 0 + 0.075*9.8*(0.5 - 0.1) - 0.035*9.8*(0.6 - 0.5)

= 0.260 N.m <<<<<<<<---------------------Answer

Note: clockwise torque taken as negative and counter clockwise torque ataken as positive.