Which of the following renders the isen-tropic relations invalid. 1. Flow is unsteady 2. Velocity is very large 3. * Gas is non-perfect 4. Changes between states 1 and 2 are finite (rather than infinitesimal) 5. Not sureWhich of the following is NOT an ex-ample of a �w or a �q process? 1. Bit of fuel inside CV ignites 2. * Gravity acts on descending CV 3. Friction acts along motion of CV 4. Pressure acts on contracting CV 5. Not sure Note: Only static internal energy changes were being considered, not kinetic energy changes� � Two fluid jets of the same density � and internal energy e flow as shown. What is the internal energy flow integral for the control volume? ⎛⎛ δˆ� �V·n⎝ e dA 1. 2�VA e 2. −2�VA e 3. * 0 4. not sure A V A V control volume n nTwo fluid jets of the same density � flow as shown. What is the kinetic en-ergy flow integral for the control vol-ume? � � 1⎛⎛ δˆ⎝� �V·n V2 dA 2 1. �V3A 2. −�V3A 3. * 0 4. not sure A V A V control volume n nAir is forced through a porous plug. What’s the expected ho(x) distribution? ho x ho x ho x 1. 2. 3. 4. Not sure 2. *Air flows out of a nozzle from a pres-surized tank at room temperature. The air comes out cold. What is the jet’s density relative to ambient? 1. * Higher 2. Same 3. Lower 4. not sureThe spacing of the cars is 40m and 4m before and after the “shock”. The shock appears stationary to a stopped pedes-trian. How fast is the obstructing ve-hicle moving? 1. 3.3 m/s 2. * 3.0 m/s 3. 2.7 m/s 4. not sure 30 m/s V = ?What is true about the temperatures T1, T2, T3, (or enthalpies h1, h2, h3) at the points shown? 1. T1 > T2 > T3 2. * T1 < T2 < T3 3. T1 < T2 = T3 4. Not enough information given 5. Not sure 1 2 3Which flow pattern is physically cor-rect? 1. 2. 3. Not sure 1. *The two flows have the same wall shape. Which flow has a larger M1 ? 1. M1 M1 2. 3. Not sure 1. *The two flows have the same M1. Which flow has a larger turning angle? 1. M1 M1 2. 3. Not sure 2. *Which is a physically-possible shock flow? 1. 2. 3. 4. 5. All are valid 6. Not sure 2. *A fan expands from M1 � 1 to near vac-uum. Approximately, what is the ex-pected turning angle? 1. � = 45� 2. � = 90� 3. * � = 130� 4. not sure 1 � = ? p 1M ~ 1 2p ~ 0A flow in a duct accelerates smoothly from M = 0.5 to M = 1.5. What must the duct look like? M x 1. 2. 3. 4. 5. Not sure 2. *Low-speed flow is drawn from a reser- voir by the exit pressure pe. pr = 100000 Pa �r = 1 kg/m 3 A = 1 m 2 Athroat = 0.5 m 2 If pe = 99000 Pa, what is m?˙1. 100 kg/s 2. * 45 kg/s 3. 22.5 kg/s 4. not sure p e r r large reservoir m . � A p A
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