In all of the experimental arrangements the mass of the knife-edge clamp is ignored. Is this an approximation because its mass is relatively small and can therefore be ignored, or is there some reason that it makes no contribution at all to the torque? Explain. 3) Measure the mass of the Aluminum "unknown" using the torque apparatus, and the volume using the vernier caliper. Then determine its density and quantitatively compare that density to the Aluminum density value listed in Appendix II of the lab manual (show all work). Your result should be a little bit high; what would be the primary cause of such an error? Explain