A 4.00 g bullet, traveling horizontally with a velocity of magnitude 400 m/s, is fired into a wooden block with mass 0.900 kg, initially at rest on a level surface. The bullet passes through the block and emerges with its speed reduced to 190 m/s. The block slides a distance of 72.0 cm along the surface from its initial position. Neglect the change of mass of the block during the interaction with the bullet, assume this interaction is momentary.
What is the coefficient of kinetic friction between block and surface?
What is the decrease in kinetic energy of the bullet?
What is the kinetic energy of the block at the instant after the bullet passes through it?
