Two magnets are sliding towards each other. one of the magnets, which has a mass of 125 grams, is moving in the positive x-direction at a speed of 7.33 m/s. the other magnet, which has a mass of 85.0 grams, is moving in the negative x-direction at a speed of 11.9 m/s. when they collide, they bind together and move as a single unit. what is the velocity of this single unit immediately after the collision?

If an object with an initial temperature of 300 k increases its temperature by 1°c every minute, by how many degrees fahrenheit will its temperature have increased in 10 minutes? (a) 6°f (b) 10°f (c) 18°f (d) 30°f

Acave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. the lift is performed in three stages, each requiring a vertical distance of 10.0 m: (a) the initially stationary spelunker is accelerated to a speed of 4.90 m/s; (b) he is then lifted at the constant speed of 4.90 m/s; (c) finally he is decelerated to zero speed. how much work is done on the 68.0 kg rescue by the force lifting him during each stage?

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.