Question

In: Mechanical Engineering

Q4. State whether the following are true or false with a brief explanation (1-2 sentences). (i)...

Q4. State whether the following are true or false with a brief explanation (1-2 sentences).

(i) Given a control volume with one inlet and two exits, the two exits must have identical mass flow rates.

(ii) You are given a control volume with one inlet and one exit such that more ‘mechanical energy’ is coming in than going out (‘mechanical energy’ is the sum of enthalpy, kinetic energy and potential energy per unit mass), but are given no information on the work or heat interactions. The total energy (Ecv) within the control volume must increase with time.

(iii) You are given a control volume where the mass is changing with time but the control volume itself has no heat or work interactions with the surroundings. The total energy within this control volume must also change with time.

(iv) For a one-inlet, one-exit control volume at steady state, the volumetric flow rates must be equal at the inlet and the exit.

(v) An open control volume (i.e., with inlets and exits), by definition, always describes the same region and therefore, the specific volume of matter inside cannot change.

Solutions

Expert Solution

1) false : For a control volume undergoing a process, the conservation of mass can be stated as:

total mass entering control volume – total mass leaving control volume = net change in mass within  control volume

2) true :

For control volumes, an additional mechanism can change the energy of a system: mass flow in and out of the control volume. Therefore, the conservation of energy for a control volume undergoing a process can be expressed as  total energy crossing boundary as heat and work + total energy of mass entering Control volume – total energy of mass leaving Control volume = net change in energy of Control volume

5) true

samet mamat answered 2 years ago
Next > < Previous

Related Solutions

Comment with a brief explanation whether the following statements are true or false: 1. The wavelength...
Comment with a brief explanation whether the following statements are true or false: 1. The wavelength of an electron moving with a velocity of 1.1*10^6 m/s is 6.6 nm. 2. In photoelectric effect, whether an electron will be ejected by light is determined not by the intensity of light but by the wavelength. 3. The temperature of a star can be determined using its radiation spectrum. 4. Resistance-temperature-detector is based on resistivity of a metal decreasing with temperature.
Q5. State whether the following are true or false with brief justifications: (i) The maximum thermal...
Q5. State whether the following are true or false with brief justifications: (i) The maximum thermal efficiency for any power cycle operating between two thermal reservoirs at temperatures T1 and T2 (T1 > T2) is 1- T2/T1. (ii) Transferring heat from a cold object to a hot object is forbidden according to the Clausius statement of the second law. (iii) A cycle that does not violate the Kelvin-Planck statement cannot violate the Clausius statement of the second law. (iv) For...
State whether each of the following six propositions is true or false. In 2-3 sentences, explain...
State whether each of the following six propositions is true or false. In 2-3 sentences, explain why. Use diagrams if helpful. a. Suppose the government passes a law requiring “profit-sharing”; every year, firms must give at least 50% of their profits to their workers. T, F, and Explain: As long as wages are flexible, wages will fall, leaving workers’ well-being unchanged. b. T, F, and Explain: With a volunteer army, wars are bad for taxpayers. With conscription, wars are bad...
State whether each of the following six propositions is true or false. In 2-3 sentences, explain...
State whether each of the following six propositions is true or false. In 2-3 sentences, explain why. Use diagrams if helpful. a. Suppose the government passes a law requiring “profit-sharing”; every year, firms must give at least 50% of their profits to their workers. T, F, and Explain: As long as wages are flexible, wages will fall, leaving workers’ well-being unchanged. b. T, F, and Explain: With a volunteer army, wars are bad for taxpayers. With conscription, wars are bad...
1. State whether the following statements are true or false. i) The trade balance is NOT...
1. State whether the following statements are true or false. i) The trade balance is NOT the most important component of the BOP. ii) The cross-border buying and selling of gold is included in the CAB. iii) When a country has a current account deficit, it means the country has accumulated foreign assets in a given period. iv) Once statistical discrepancies are taken into account, the BOP is always balanced.
(a) State whether True or False and provide an explanation (or an example): If preferences are...
(a) State whether True or False and provide an explanation (or an example): If preferences are convex then the utility function must also always be convex. (b) Is U=(5x1+10x2)2 a monotonic transformation of U=x1+x2? Explain.
Answer true or false, with a brief explanation. 1. Monopolies are always bad for consumers. 2....
Answer true or false, with a brief explanation. 1. Monopolies are always bad for consumers. 2. The supply curve of a monopolist is upward sloping. 3. Monopolies charge the highest price a consumer is willing to pay, thus capturing all consumer surplus.
Indicate whether the following statements are true or false. Provide an explanation for your answer: i....
Indicate whether the following statements are true or false. Provide an explanation for your answer: i. In a perfectly competitive market an increase in demand for a product may increase prices in the short run but not in the long run. ii. The "invisible hand" is a metaphor for how societies create laws to regulate what and how things are produced in an economy. iii. The opportunity cost of an item or an action is always equal to the amount...
1. State whether the following statements are true or false. i) An enzyme catalyst DOES alter...
1. State whether the following statements are true or false. i) An enzyme catalyst DOES alter the equilibrium constant for a reaction. ii) The presence of an enzyme catalyst DOES NOT decrease the energy required to reach the transition state. iii) An enzyme catalyst DOES affect the rate of a biochemical reaction. iv) The presence of an enzyme catalyst DOES NOT decrease the change in free energy (Gfinal - Ginitial) of the overall reaction. 2. True or False? Due to...
Indicate whether each statement is true or false. If the statement is false, provide a brief explanation of why it is false. 1. A disclosed basis of accounting is GAAP.
Indicate whether each statement is true or false. If the statement is false, provide a brief explanation of why it is false.1. A disclosed basis of accounting is GAAP.2. An audit opinion can be provided on a disclosed basis of accounting.3. A disclosed basis of accounting is used to provide more useful information for the users.4. Note disclosure is required if a disclosed basis of accounting is used.5. A public company can use a disclosed basis of accounting.
ADVERTISEMENT
Subjects
ADVERTISEMENT
Latest Questions
ADVERTISEMENT