A wheel with radius 0.33m and rotational inertia 2.0kgm2 spins on an axle with an initial angular speed of 3.0 rad/s .Friction in the axle exerts a torque on the wheel, causing the wheel to stop after 6.0s .The average torque exerted on the wheel as it slows down has magnitude

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.

What object a collides with object b and bounces back its final momentum is?

If two parallel light rays hit a mirror, they will not be parallel to each other after they reflect.