Chapter 9, Problem 9.77P

Two metal disks, one with radius R₁ = 2.50 cm and mass M₁ = 0.80 kg and the other with radius R₂ = 5.00 cm and mass R₂ = 1.60 kg, are welded together and mounted on a frictionless axis through their common center (Fig. P9.77). (a) What is the total moment of inertia of the two disks? (b) A light string is wrapped around the edge of the smaller disk, and a 1.50-kg block is suspended from the free end of the string. If the block is released from rest at a distance of 2.00 m above the floor, what is its speed just before it strikes the floor? (c) Repeat part (b), this time with the string wrapped around the edge of the larger disk. In which case is the final speed of the block greater? Explain

Figure P9.77