A uniform meter stick of mass 40 g is used to suspend three objects as follows: 20 g at 0.13 m, 25 g at 0.41 m and 40 g at 0.64 m. Where could you place your finger to balance the stick in the horizontal position?

Answer 1

Put your finger at a point x so that the moments due to all three weights and the ruler weight (considered to be applied at the center of mass) add up to zero. The only unknown will be x.
20*(x-13) + 25*(x-41) + 40*(x-50) +40(*(x-64) = 0

Solve for x, in cm

Answer 2

Hi drwls:

I had a question about this one. Don't we have to convert the weights into newtons for this problem and the distance to meters since torque is in Nm?

Answer 3

whhere did u get this part from:
40*(x-50), the 40 is the mass of the ruler but what about the 50?

Answer 4

9.8 would cancel everywhere, so it isn't necessary if you're merely searching for distance