A 23 g bullet travelling at 230 m/s penetrates a 2.0 kg block of wood and emerges cleanly out the other side traveling 170 m/s. If the block is stationary on a frictionless surface, how fast does it move after the collision? Round your answer to one decimal place and include units.

and

Two carts start at rest, side by side. The mass of cart 1 is 0.505 kg. A spring was activated between the carts and the two carts moved away from one another, at the indicated velocities. Determine the mass of cart 2.

Round your answer to one decimal place and include units.