(II) A square uniform raft, 18 m by 18 m, of mass 6200 kg, is used as a ferryboat. If three cars, each of mass 1350 kg, occupy the NE, SE, and SW corners, determine the CM of the loaded ferryboat relative to the center of the raft.

b) A vertical pile of mass 150 kg is driven 120 mm into the ground by the blow of a 1100 kg hammer, which falls through 800 mm. assuming the hammer and pile remain in contact, determine the following: i) The velocity of the hammer just before impact ii) The velocity immediately after impact iii) The resistive force of the ground, assuming it to be uniform

(3) This problem deals with a method for measuring the muzzle velocity of a rifle. A rifle with unknown muzzle velocity vo fires a bullet with mass m into a large block of wood with mass M that is sitting on a horizontal surface. The velocity of the block right after the (inelastic) collision is v. The block then slides a distance d along the surface and comes to a stop. The coefficient of kinetic friction between the block of wood and the surface is μk. (a) Use conservation of momentum (during the collision) and the work-energy theorem (after the collision) to show that the muzzle velocity of the rifle is given by: 20 = (m + M) √2 µx8d m (b) Calculate the muzzle velocity of the rifle if m= 5.00 g. M = 1.20 kg. d = 14.6 cm, and µ = 0.56. [answer: vo = 305 m/s]