# Halliday物理習題求解

3. Figure 9-36 shows a slab with dimensions d1 = 11.0 cm, d2 = 2.80 cm, and d3 = 13.0 cm. Half the slab consists of aluminum (density = 2.70 g/cm3) and half consists of iron (density = 7.85 g/cm3). What are (a) the x coordinate, (b) the y coordinate, and (c) the z coordinate of the slab's center of mass?

44. In Fig. 9-57, a stationary block explodes into two pieces L and R that slide across a frictionless floor and then into regions with friction, where they stop. Piece L, with a mass of 2.0 kg, encounters a coefficient of kinetic friction μL = 0.40 and slides to a stop in distance dL = 0.15 m. Piece R encounters a coefficient of kinetic friction μR = 0.50 and slides to a stop in distance dR = 0.25 m. What was the mass of the block?

51. In Fig. 9-58a, a 3.50 g bullet is fired horizontally at two blocks at rest on a frictionless table. The bullet passes through block 1 (mass 1.20 kg) and embeds itself in block 2 (mass 1.80 kg). The blocks end up with speeds v1 = 0.630 m/s and v2 = 1.40 m/s (Fig. 9-58b). Neglecting the material

removed from block 1 by the bullet, find the speed of the bullet as it (a) leaves and (b) enters block 1.