Apellet gun is shot at a cardboard box of mass m2 = 0.65 kg on a frictionless surface. the pellet has a mass of m1 = 0.0145 kg and flys at a velocity of v1 = 79 m/s. it is observed that the box is moving at a velocity of v2 = 0.43 m/s after the pellet goes through it.1. write an expression for the magnitude of the bb's velocity as it exits the box vf.
2. what is the bb's final velocity vf, in meters per second?
3. if the bb doesn't exit the box, what will the velocity of the box v'2, be in meters per second?

As part of an industrial process, air as an ideal gas at 10 bar, 400k expands at steady state through a valve to a pressure of 4 bar. the mass flow rate of air is 0.5 kg/s. the air then passes through a heat exchanger where it is cooled to a temperature of 295k with negligible change in pressure. the valve can be modeled as a throttling process, and kinetic and potential energy effects can be neglected. (a) for a control volume enclosing the valve and heat exchanger and enough of the local surroundings that the heat transfer occurs at the ambient temperature of 295 k, determine the rate of entropy production, in kw/k. (b) if the expansion valve were replaced by an adiabatic turbine operating isentropically, what would be the entropy production? compare the results of parts (a) and (b) and discuss.

Idon’t quite understand this problem

You have a pick-up truck that weighed 4,000 pounds when it was new. you are modifying it to increase its ground clearance. when you are finished