A 4900 kg open train car is rolling on frictionless rails at 27 m/sm/s when it starts pouring rain. Rain falls vertically. A few minutes later, the car's speed is 23 m/s. What mass of water has collected in the car?

A gun fires a bullet vertically into a 1.40-kgkg block of wood at rest on a thin horizontal sheet. If the bullet has a mass of 13.5 g and a speed of 310 m/s, how high will the block rise into the air after the bullet becomes embedded in it? Answer in meters.

Cuttlefish use jet propulsion to move rapidly. To do this, a cuttlefish fills its muscular mantle cavity with water and then quickly expels the water through a tube-like opening. The mass of a cuttlefish is about the same as the mass of water of the same volume. A 14-cm-long and 6.0-cm-wide cuttlefish, initially at rest, is moving at a speed of 4.0 m/sm/s after expelling the water from its body. Assume that the cuttlefish has a cylindrical form, the mantle cavity has a form of a cylinder with a length of 9.0 cm, and the thickness of the muscle surrounding the sides of the cavity is 1.0 cm. Estimate the speed of the expelled water relative to the sea bed. Express your answer with the appropriate units.

A 55.0 kg boy runs at a speed of 16.0m/s and jumps onto a cart that is initially at rest. The boy and the cart then move off together at a speed of 2.50m/s. What is the mass of the cart?