# Homework Help: Thermodynamics Conceptual Question

1. Mar 18, 2010

### boeing9379

1. The problem statement, all variables and given/known data

I have a system with air flowing through a ducting with two inlets and one exit operating at steady state. There is no heat transfer or potential energy change. I know the mass flow rates and velocities at all inlets and exits. How would I go about finding the rate of change in kinetic energy for the stream flowing from point 2, an inlet, to point 3, the outlet.

2. Relevant equations

3. The attempt at a solution

I don't know exactly what the rate of change of kinetic energy between one of the inlets and the exit means, so I don't know where to start.

2. Mar 23, 2010

### crims0ned

Maybe the rate of change in the kinetic energies of the inlets and outlet per minute or second? $$K.E. = \frac{1}{2}mv^2$$

Last edited: Mar 23, 2010
3. Mar 23, 2010

### rock.freak667

Adding to what crims0ned suggested

$$\frac{d}{dt}(KE) = \frac{1}{2} \dot{m}v^2$$