These are questions related to causes of friction!
Help is appreciated ^.^


If we repeat the slide of the plastic but wet the table first, what will happen? More friction or less?

If we spray a little oil on the wet table and repeat the sliding experiment, what will happen?

What would happen if you tried to slide a rubber eraser across the table? Why?

What should the power status of a circuit be when measuring resistance with an ohmmeter?

An inclined plane wrapped around a metal shaft is a a. lever b. screw c. pulley d. wedge

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.