Introduction: To complete this activity, a stairway was used in the main hallway and was measured with a meterstick. The height of the staircase is 4.84 meters. The student was asked to step on a bathroom scale to measure
their weight in pounds. Scale weight = 104.89 lbs. (2.2 lbs. - 1 kg). Then during the day, times were noted for
having to walked, trotted, and ran up the staircase. Walking time; 14.99 sec, trotting time; 9.85 sec running time;
6.40 sec
Purpose: This activity is used to develop the concepts of work, energy, and power as a student was measured for
work, potential energy, their power level, and the speed in which they climbed a staircase during a typical school
day

What is work? how much work is done to move an object 0 meters?

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.

Why are graphs useful when interpreting data