Thermodynamics: An Engineering Approach
9th Edition
ISBN: 9781259822674
Author: Yunus A. Cengel Dr., Michael A. Boles
Publisher: McGraw-Hill Education
expand_more
expand_more
format_list_bulleted
Textbook Question
Chapter 2.8, Problem 1P
What is the difference between the macroscopic and microscopic forms of energy?
Expert Solution & Answer
To determine
The difference between macroscopic and microscopic forms of energy.
Explanation of Solution
The difference between the macroscopic and microscopic forms of energy is discussed as below in the tabular form.
S. No. | Macroscopic | Microscopic |
1. | It is a type of energy where the system is related with motion and external effects. | It is a type of energy where the system is related with molecular structure and its activities. |
2. | The kinetic and potential energy are the form of macroscopic as they are displayed as outside reference frame. | The internal energy is the form of microscopic as it is independent of outside reference frames. |
3. | The approach used in the macroscopic form is simple mathematical formulae. | The approach used in the microscopic form is advanced mathematical formulae. |
Want to see more full solutions like this?
Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
20
3.
2-233
2520
Тр
Gears
1079
A pair of helical gears consist of a 20 teeth pinion meshing with a 100 teeth gear. The pinion rotates at
Ta
720 r.p.m. The normal pressure angle is 20° while the helix angle is 25°. The face width is 40 mm and
the normal module is 4 mm. The pinion as well as gear are made of steel having ultimate strength of
600 MPa and heat treated to a surface hardness of 300 B.H.N. The service factor and factor of safety
are 1.5 and 2 respectively. Assume that the velocity factor accounts for the dynamic load and calculate
the power transmitting capacity of the gears.
[Ans. 8.6 kW
4. A single stage helical gear reducer is to receive power from a 1440 r.p.m., 25 kW induction motor. The
gear tooth profile is involute full depth with 20° normal pressure angle. The helix angle is 23°,
number of teeth on pinion is 20 and the gear ratio is 3. Both the gears are made of steel with allowable
beam stress of 90 MPa and hardness 250 B.H.N.
(a) Design the gears for 20% overload carrying capacity from standpoint of bending strength and
wear,
(b) If the incremental dynamic load of 8 kN is estimated in tangential plane, what will be the safe
power transmitted by the pair at the same speed?
Determine the stress in each section of the bar shown in Fig. when subjected to an
axial tensile load shown in Fig. The central section is 30 mm hollow square cross-
section; the other portions are of circular section, their diameters being indicated
What will be the total deformation of the bar? For the bar material E = 210GPa.
20mi
О
30mm
30mmm
2.6
15mm
30kN
1
2
10kN
- 20kN
3
-329 91mm
100mm
371mm
Chapter 2 Solutions
Thermodynamics: An Engineering Approach
Ch. 2.8 - What is the difference between the macroscopic and...Ch. 2.8 - What is total energy? Identify the different forms...Ch. 2.8 - List the forms of energy that contribute to the...Ch. 2.8 - How are heat, internal energy, and thermal energy...Ch. 2.8 - What is mechanical energy? How does it differ from...Ch. 2.8 - Portable electric heaters are commonly used to...Ch. 2.8 - Natural gas, which is mostly methane CH4, is a...Ch. 2.8 - Consider the falling of a rock off a cliff into...Ch. 2.8 - Electric power is to be generated by installing a...Ch. 2.8 - The specific kinetic energy of a moving mass is...
Ch. 2.8 - Determine the specific kinetic energy of a mass...Ch. 2.8 - Calculate the total potential energy, in Btu, of...Ch. 2.8 - Determine the specific potential energy, in kJ/kg,...Ch. 2.8 - An object whose mass is 100 kg is located 20 m...Ch. 2.8 - A water jet that leaves a nozzle at 60 m/s at a...Ch. 2.8 - Consider a river flowing toward a lake at an...Ch. 2.8 - At a certain location, wind is blowing steadily at...Ch. 2.8 - What is the caloric theory? When and why was it...Ch. 2.8 - In what forms can energy cross the boundaries of a...Ch. 2.8 - What is an adiabatic process? What is an adiabatic...Ch. 2.8 - When is the energy crossing the boundaries of a...Ch. 2.8 - Consider an automobile traveling at a constant...Ch. 2.8 - A room is heated by an iron that is left plugged...Ch. 2.8 - A room is heated as a result of solar radiation...Ch. 2.8 - A gas in a pistoncylinder device is compressed,...Ch. 2.8 - A small electrical motor produces 5 W of...Ch. 2.8 - A car is accelerated from rest to 85 km/h in 10 s....Ch. 2.8 - A construction crane lifts a prestressed concrete...Ch. 2.8 - Determine the torque applied to the shaft of a car...Ch. 2.8 - A spring whose spring constant is 200 lbf/in has...Ch. 2.8 - How much work, in kJ, can a spring whose spring...Ch. 2.8 - A ski lift has a one-way length of 1 km and a...Ch. 2.8 - The engine of a 1500-kg automobile has a power...Ch. 2.8 - A damaged 1200-kg car is being towed by a truck....Ch. 2.8 - As a spherical ammonia vapor bubble rises in...Ch. 2.8 - A steel rod of 0.5 cm diameter and 10 m length is...Ch. 2.8 - What are the different mechanisms for transferring...Ch. 2.8 - For a cycle, is the net work necessarily zero? For...Ch. 2.8 - On a hot summer day, a student turns his fan on...Ch. 2.8 - Water is being heated in a closed pan on top of a...Ch. 2.8 - An adiabatic closed system is accelerated from 0...Ch. 2.8 - A fan is to accelerate quiescent air to a velocity...Ch. 2.8 - A vertical pistoncylinder device contains water...Ch. 2.8 - At winter design conditions, a house is projected...Ch. 2.8 - A water pump increases the water pressure from 15...Ch. 2.8 - The lighting needs of a storage room are being met...Ch. 2.8 - A university campus has 200 classrooms and 400...Ch. 2.8 - Consider a room that is initially at the outdoor...Ch. 2.8 - An escalator in a shopping center is designed to...Ch. 2.8 - Consider a 2100-kg car cruising at constant speed...Ch. 2.8 - Prob. 51PCh. 2.8 - What is mechanical efficiency? What does a...Ch. 2.8 - How is the combined pumpmotor efficiency of a pump...Ch. 2.8 - Can the combined turbinegenerator efficiency be...Ch. 2.8 - Consider a 2.4-kW hooded electric open burner in...Ch. 2.8 - The steam requirements of a manufacturing facility...Ch. 2.8 - Reconsider Prob. 256E. Using appropriate software,...Ch. 2.8 - A 75-hp (shaft output) motor that has an...Ch. 2.8 - Prob. 59PCh. 2.8 - An exercise room has six weight-lifting machines...Ch. 2.8 - A room is cooled by circulating chilled water...Ch. 2.8 - The water in a large lake is to be used to...Ch. 2.8 - A 7-hp (shaft) pump is used to raise water to an...Ch. 2.8 - A geothermal pump is used to pump brine whose...Ch. 2.8 - At a certain location, wind is blowing steadily at...Ch. 2.8 - Reconsider Prob. 265. Using appropriate software,...Ch. 2.8 - Water is pumped from a lower reservoir to a higher...Ch. 2.8 - An 80-percent-efficient pump with a power input of...Ch. 2.8 - Water is pumped from a lake to a storage tank 15 m...Ch. 2.8 - Large wind turbines with a power capacity of 8 MW...Ch. 2.8 - A hydraulic turbine has 85 m of elevation...Ch. 2.8 - The water behind Hoover Dam in Nevada is 206 m...Ch. 2.8 - An oil pump is drawing 44 kW of electric power...Ch. 2.8 - A wind turbine is rotating at 15 rpm under steady...Ch. 2.8 - How does energy conversion affect the environment?...Ch. 2.8 - What is acid rain? Why is it called a rain? How do...Ch. 2.8 - Why is carbon monoxide a dangerous air pollutant?...Ch. 2.8 - What is the greenhouse effect? How does the excess...Ch. 2.8 - What is smog? What does it consist of? How does...Ch. 2.8 - Consider a household that uses 14,000 kWh of...Ch. 2.8 - When a hydrocarbon fuel is burned, almost all of...Ch. 2.8 - Prob. 82PCh. 2.8 - A typical car driven 20,000 km a year emits to the...Ch. 2.8 - Prob. 84PCh. 2.8 - What are the mechanisms of heat transfer?Ch. 2.8 - Which is a better heat conductor, diamond or...Ch. 2.8 - How does forced convection differ from natural...Ch. 2.8 - What is a blackbody? How do real bodies differ...Ch. 2.8 - Define emissivity and absorptivity. What is...Ch. 2.8 - Does any of the energy of the sun reach the earth...Ch. 2.8 - The inner and outer surfaces of a 5-m 6-m brick...Ch. 2.8 - The inner and outer surfaces of a 0.5-cm-thick 2-m...Ch. 2.8 - Reconsider Prob. 292. Using appropriate software,...Ch. 2.8 - Prob. 94PCh. 2.8 - Prob. 95PCh. 2.8 - Prob. 96PCh. 2.8 - Prob. 97PCh. 2.8 - For heat transfer purposes, a standing man can be...Ch. 2.8 - Prob. 99PCh. 2.8 - Prob. 100PCh. 2.8 - A 1000-W iron is left on the ironing board with...Ch. 2.8 - A 7-cm-external-diameter, 18-m-long hot-water pipe...Ch. 2.8 - A thin metal plate is insulated on the back and...Ch. 2.8 - Reconsider Prob. 2103. Using appropriate software,...Ch. 2.8 - The outer surface of a spacecraft in space has an...Ch. 2.8 - Prob. 106PCh. 2.8 - A hollow spherical iron container whose outer...Ch. 2.8 - Some engineers have developed a device that...Ch. 2.8 - Consider a classroom for 55 students and one...Ch. 2.8 - Consider a homeowner who is replacing his...Ch. 2.8 - Prob. 111RPCh. 2.8 - The U.S. Department of Energy estimates that...Ch. 2.8 - A typical household pays about 1200 a year on...Ch. 2.8 - Prob. 114RPCh. 2.8 - Prob. 115RPCh. 2.8 - Prob. 116RPCh. 2.8 - Consider a TV set that consumes 120 W of electric...Ch. 2.8 - Water is pumped from a 200-ft-deep well into a...Ch. 2.8 - Consider a vertical elevator whose cabin has a...Ch. 2.8 - Prob. 120RPCh. 2.8 - In a hydroelectric power plant, 65 m3/s of water...Ch. 2.8 - The demand for electric power is usually much...Ch. 2.8 - The pump of a water distribution system is powered...Ch. 2.8 - Prob. 124RPCh. 2.8 - A 2-kW electric resistance heater in a room is...Ch. 2.8 - Prob. 126FEPCh. 2.8 - A 75-hp compressor in a facility that operates at...Ch. 2.8 - On a hot summer day, the air in a well-sealed room...Ch. 2.8 - A fan is to accelerate quiescent air to a velocity...Ch. 2.8 - A 900-kg car cruising at a constant speed of 60...Ch. 2.8 - Prob. 131FEPCh. 2.8 - Prob. 132FEPCh. 2.8 - A 2-kW pump is used to pump kerosene ( = 0.820...Ch. 2.8 - Prob. 134FEPCh. 2.8 - Prob. 135FEPCh. 2.8 - Prob. 136FEPCh. 2.8 - Prob. 137FEPCh. 2.8 - Heat is transferred steadily through a...Ch. 2.8 - The roof of an electrically heated house is 7 m...
Additional Engineering Textbook Solutions
Find more solutions based on key concepts
How does a computers main memory differ from its auxiliary memory?
Java: An Introduction to Problem Solving and Programming (8th Edition)
Look at the following description of a problem domain:
Starting Out with Java: From Control Structures through Data Structures (4th Edition) (What's New in Computer Science)
Why is the study of database technology important?
Database Concepts (8th Edition)
A nozzle at A discharges water with an initial velocity of 36 ft/s at an angle with the horizontal. Determine ...
Vector Mechanics For Engineers
How are relationships between tables expressed in a relational database?
Modern Database Management
Assume a telephone signal travels through a cable at two-thirds the speed of light. How long does it take the s...
Electric Circuits. (11th Edition)
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.Similar questions
- Calculate the load that will make point A move to the left by 6mm, E=228GPa. The diameters of the rods are as shown in fig. below. 2P- PA 80mm B 200mm 2P 0.9m 1.3m.arrow_forwardIf the rods are made from a square section with the dimension as shown. Calculate the load that will make point A move to the left by 6mm, E=228GPa. 2P- P A 80mm B 200mm 2P 0.9m 1.3marrow_forward3. 9. 10. The centrifugal tension in belts (a) increases power transmitted (b) decreases power transmitted (c) have no effect on the power transmitted (d) increases power transmitted upto a certain speed and then decreases When the belt is stationary, it is subjected to some tension, known as initial tension. The value of this tension is equal to the (a) tension in the tight side of the belt (b) tension in the slack side of the belt (c) sum of the tensions in the tight side and slack side of the belt (d) average tension of the tight side and slack side of the belt The relation between the pitch of the chain (p) and pitch circle diameter of the sprocket (d) is given by 60° (a) p=d sin (c) p=d sin (120° T where T Number of teeth on the sprocket. 90° (b) p=d sin T 180° (d) p=d sin Tarrow_forward
- OBJECTIVE TYPE QUESTIONS 1. The maximum fluctuation of energy is the 2. (a) sum of maximum and minimum energies (b) difference between the maximum and minimum energies (c) ratio of the maximum energy and minimum energy (d) ratio of the mean resisting torque to the work done per cycle In a turning moment diagram, the variations of energy above and below the mean resisting torque line is called (a) fluctuation of energy (b) maximum fluctuation of energy (c) coefficient of fluctuation of energy (d) none of the above Chapter 16: Turning Moment Diagrams and Flywheel 611 The ratio of the maximum fluctuation of speed to the mean speed is called 3. (a) fluctuation of speed (c) coefficient of fluctuation of speed 4. (b) maximum fluctuation of speed (a) none of these The ratio of the maximum fluctuation of energy to the.......... is called coefficient of fluctuation of energy. (a) minimum fluctuation of energy (b) work done per cycle The maximum fluctuation of energy in a flywheel is equal to 5.…arrow_forwardOBJECTIVE TYPE QUESTIONS 1. The velocity ratio of two pulleys connected by an open belt or crossed belt is 2. (a) directly proportional to their diameters (b) inversely proportional to their diameters (c) directly proportional to the square of their diameters (d) inversely proportional to the square of their diameters Two pulleys of diameters d, and d, and at distance x apart are connected by means of an open belt drive. The length of the belt is (a)(d+d₁)+2x+ (d₁+d₂)² 4x (b)(d₁-d₂)+2x+ (d₁-d₂)² 4x (c)(d₁+d₂)+ +2x+ (d₁-d₂)² 4x (d)(d-d₂)+2x+ (d₁ +d₂)² 4x 3. In a cone pulley, if the sum of radii of the pulleys on the driving and driven shafts is constant, then (a) open belt drive is recommended (b) cross belt drive is recommended (c) both open belt drive and cross belt drive are recommended (d) the drive is recommended depending upon the torque transmitted Due to slip of the belt, the velocity ratio of the belt drive 4. (a) decreases 5. (b) increases (c) does not change When two pulleys…arrow_forwardQ3: (10 MARKS) A piston with a weight of 29.4 N is supported by a spring and dashpot. A dashpot of damping coefficient c = 275 N.s/m acts in parallel with the spring of stiffness k = 2400 N/m. A fluctuating pressure p = 960 sin 30t N/m² acts on the piston, whose top surface area is 0.05 m². Determine the steady-state displacement as a function of time and the maximum force transmitted to the base. P=Po sin cot Warrow_forward
- 9. Design a spur gear drive required to transmit 45 kW at a pinion speed of 800 r.p.m. The velocity ratio is 3.5 : 1. The teeth are 20° full-depth involute with 18 teeth on the pinion. Both the pinion and gear are made of steel with a maximum safe static stress of 180 MPa. Assume a safe stress of 40 MPa for the material of the shaft and key. 10. Design a pair of spur gears with stub teeth to transmit 55 kW from a 175 mm pinion running at 2500 r.p.m. to a gear running at 1500 r.p.m. Both the gears are made of steel having B.H.N. 260. Approximate the pitch by means of Lewis equation and then adjust the dimensions to keep within the limits set by the dynamic load and wear equation.arrow_forward7. A motor shaft rotating at 1440 r.p.m. has to transmit 15 kW to a low speed shaft rotating at 500 r.p.m. The teeth are 20° involute with 25 teeth on the pinion. Both the pinion and gear are made of cast iron with a maximum safe stress of 56 MPa. A safe stress of 35 MPa may be taken for the shaft on which the gear is mounted. Design and sketch the spur gear drive to suit the above conditions. The starting torque may be assumed as 1,25 times the running torque. Ruins 20 LW at 100 nm to another shaft running approxiarrow_forward6. A two stage reduction drive is to be designed to transmit 2 kW; the input speed being 960 r.p.m. and overall reduction ratio being 9. The drive consists of straight tooth spur gears only, the shafts being spaced 200 mm apart, the input and output shafts being co-axial.arrow_forward
- 2 A metal block of mass m = 10 kg is sliding along a frictionless surface with an initial speed Vo, as indicated below. The block then slides above an electromagnetic brake that applies a force FEB to the block, opposing its motion. The magnitude of the electromagnetic force varies quadratically with the distance moved along the brake (x): 10 FEB = kx², with k = 5 N m² V₁ = 8 m/s m = 10 kg FEB Frictionless surface Electromagnetic brake ⇒x Determine how far the block slides along the electromagnetic brake before stopping, in m.arrow_forwardQ1: Determine the length, angle of contact, and width of a 9.75 mm thick leather belt required to transmit 15 kW from a motor running at 900 r.p.m. The diameter of the driving pulley of the motor is 300 mm. The driven pulley runs at 300 r.p.m. and the distance between the centers of two pulleys is 3 meters. The density of the leather is 1000 kg/m³. The maximum allowable stress in the leather is 2.5 MPa. The coefficient of friction between the leather and pulley is 0.3. Assume open belt drive.arrow_forward5. A 15 kW and 1200 r.p.m. motor drives a compressor at 300 r.p.m. through a pair of spur gears having 20° stub teeth. The centre to centre distance between the shafts is 400 mm. The motor pinion is made of forged steel having an allowable static stress as 210 MPa, while the gear is made of cast steel having allowable static stress as 140 MPa. Assuming that the drive operates 8 to 10 hours per day under light shock conditions, find from the standpoint of strength, 1. Module; 2. Face width and 3. Number of teeth and pitch circle diameter of each gear. Check the gears thus designed from the consideration of wear. The surface endurance limit may be taken as 700 MPa. [Ans. m = 6 mm; b= 60 mm; Tp=24; T=96; Dp = 144mm; DG = 576 mm]arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Refrigeration and Air Conditioning Technology (Mi...Mechanical EngineeringISBN:9781305578296Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill JohnsonPublisher:Cengage Learning
Refrigeration and Air Conditioning Technology (Mi...
Mechanical Engineering
ISBN:9781305578296
Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson
Publisher:Cengage Learning
Heat Transfer – Conduction, Convection and Radiation; Author: NG Science;https://www.youtube.com/watch?v=Me60Ti0E_rY;License: Standard youtube license