This time, put a known weight of 200 grams on one end and an unknown weight on the other, and slide the clamp bearing the known weight until equilibrium is reached. Put on record the positions of both weights and weigh the one with unknown mass.
One such instance of applying equilibrium of rigid body is when one desires to find the mass or weight of an object given masses of other materials that can be put on balance and adjusted to equilibrium. For instance, a setup where the shaft, lever, and handle are welded together which can be worked by modifying forces on certain regions so as to facilitate or prevent rotation of the rigid structure.
(1) Compute the weight of the meter stick from the data of Procedure 4 by the method of moments. Compare your result with that obtained by direct weighing of the stick. In particular, note whether the two measurements agree within the errors associated with each.
(2) Using the point of support as the axis in Procedure 5, compute the moment of force of each of the weights and also of the meter stick, assuming its weight to be concentrated at its center of gravity. Add all these moments together, paying attention to their algebraic signs. Compare this net torque with zero, noting in particular whether zero lies within the error associated with your result.
Solution: Using torque (τ) = force * distance for each moment about the new point of balance where forces to the left of the balance point may be treated with negative moments and forces to the right of such point with positive moments by convention, then
(3) Compute the weight of the body used in Procedure 6 by the method of moments. Compare the measured weight of this body with the computed weight, noting in particular whether the two weights agree within the experimental errors involved.
In the experiment, the summation of forces exerted by the weights, the support clamp, as well as