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Unformatted text preview: this, we can get: Next, we want to express the momentum change in terms of velocity and mass. However, first we must
account for the 10% energy loss due to the collision (KE2=0.9KE1). Cancelling terms and solving for v2x in terms of v1x gives: Now, we can find the change in momentum: Substitution back into the equation for pressure gives: Next, we can relate vx to T by the equations: The second of those equations comes from the assumption of isentropic motion in which the particle’s
velocity components are equal in magnitude. Using substitution: Substituting this expression into the pressure equation gives: Nk=nR, so the final expression is: 3. System: Closed, control mass
Assume: Neglect kinetic and potential energy
Given: = 3 kW, = 2.4t kW for 0 < t < 1 hour and 2.4 kW for t > 1 hour. The units for power and heat
transfer rate are kW (kJ/s). When you input the value of t into the piecewise function, it should be in
hours even though the power output still will have kW as the unit.
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- Winter '14