A bullet of mass 6.3 g is fired horizontally into a 1.2 kg wooden block at rest on a horizontal surface. The coefficient of kineticfriction between block and surface is 0.25. The bullet stops in the block, which slides straight ahead for 2.7 m (without rotation). (a) What is the speed of the block immediately after the bullet stops relative to it? (b) At what speed is the bullet fired?