Concept explainers
The heat engines among the motor engines.
Answer to Problem 1CQ
choice (a) an automobile engine and (c) a steam turbine.
Explanation of Solution
In
Write an expression for the heat input from the hot reservoir,
Here,
Conclusion:
In an automobile, an internal combustion engine is developing heat internally. This heat is converted into mechanical work. Since the heat is developed internally, extraction of heat from an external source does not occur. Thus, choice (a) is correct.
The steam turbine has an external combustion engine. Here, the engine obtains the energy to produce the superheated steam from heating outside of the turbine. Thus, choice (c) is correct.
In electrical motors, conversion of electrical energy to work occurs. Thus, choice (b) is incorrect.
Want to see more full solutions like this?
Chapter 11 Solutions
PHYSICS OF EVERYDAY (LL) W/ACCESS CODE
- The first law of thermodynamics and the conservation of energy, as discussed in Conservation of Energy, ale cleanly related. How do they differ in the types of energy considered?arrow_forwardA 4ton air conditioner removes 5.60107J (48,000 British thermal units) from a cold environment in 1.00 h. (a) What energy input in joules is necessary to do this if the air conditioner has an energy efficiency rating (EER) of 12.0? (b) What is the cost of doing this if the work costs 10.0 cents per 3.60106J (one kilowatt—hour)? (c) Discuss whether this cost seems realistic. Note that the energy efficiency rating (EER) of an air conditioner or refrigerator is defined to be the number of British thermal units of heat transfer from a cold environment per hour divided by the watts of power input.arrow_forward€69. Integrated Concepts (a) A large electrical power facility produces 1600 MW of “waste heat.” which is dissipated to the environment in cooling towers by warming air flowing through the towers by 500C. What is the necessary flow rate of air in m3/s ? (b) Is your result consistent with the large cooling towers used by many large electrical power plants?arrow_forward
- Shoveling snow can be extremely taxing because the arms have such a low efficiency in this activity. Suppose a person shoveling a footpath metabolizes food at the rate of 800 W. (a) What is her useful power output? (b) How long will it take her to lift 3000 kg of snow 1.20 m? (This could be the amount of heavy snow on 20 m of footpath.) (c) How much waste heat transfer in kilojoules will she generate in the process?arrow_forwardA 75-kg sprinter accelerates from rest to a speed of 11.0 m/s in 5.0 s. (a) Calculate the mechanical work done by the sprinter during this time. (b) Calculate the average power the sprinter must generate. (c) If the sprinter converts food energy to mechanical energy with an efficiency of 25%, at what average rate is he burning Calories? (d) What happens to the other 75% of the food energy being used?arrow_forwardWork done on a system puts energy into it Work done by a system removes energy from it Give an example for each statement.arrow_forward
- Energy is the mistress of the Universe, and entropy is her shadow. Writing for an audience of general readers, argue for this statement with at least two examples. Alternatively, argue for the view that entropy is like an executive who instantly determines what will happen, whereas energy is like a bookkeeper telling us how little we can afford. (Arnold Sommerfeld suggested the idea for this question.)arrow_forwarda coal fired power station is a huge hit engine. it uses hit transfer from burning coal to do work to turn turbines , which are use to generate electricity in a single day, a large coal power station has 2.50*10^24 J of hit transfer from coal and 1.48*10^14 J of heat transfer into environment. What is the work done by the power station? What is the efficiency of power station?arrow_forwardA geothermal heating system is installed outside a house by laying pipesunderground, as shown in the image.The heat is transferred from the ground to the pipes to keep the house warm. How does this system of heating the house reduce the impact on the natural environment?A by providing energy to the groundB by conserving underground energyC by using a sustainable source of energyD by transforming one form of energy to anotherarrow_forward
- Wind farms in Washington have a capacity of 3075 Megawatts (mega means million remember so this is 3075000000 watts). This means if they were all operating at the same time this is how many Joules per second they would produce. a) Assume all wind farms in Washington are operating at capacity. How much energy in Kwh is produced in one hour? b) Now it is not windy all the time, so suppose only 60% of the wind farms are operating. How much energy is produced in a 7 day week by these wind farms c) An average home uses about 250 KWh for a 7 day week. How many homes can be operated by the wind farms in part barrow_forwardConverting sunlight to electricity with solar cells has an efficiency of 15%. It's possible to achieve a higher efficiency (though currently at higher cost) by using concentrated sunlight as the hot reservoir of a heat engine. Each dish in (Figure 1) concentrates sunlight on one side of a heat engine, producing a hot-reservoir temperature of 560 ∘C. The cold reservoir, ambient air, is approximately 30 ∘C. The actual working efficiency of this device is 30%. What is the theoretical maximum efficiency?arrow_forward11. A 56kg weight lifter has to carry a 1000lbs of load 10meters above his current location. Determine the amount of energy needed in kcal. Derive with the formula below, show the cancellation, explain the step by step and DRAW a free body diagram/figure. refer with this: PE1 + KE1 + U1 + WF1 + Q1 + W1 = PE2 + KE2 + U2 + WF2 + Q2 + W2 + E losses.arrow_forward
- Glencoe Physics: Principles and Problems, Student...PhysicsISBN:9780078807213Author:Paul W. ZitzewitzPublisher:Glencoe/McGraw-HillCollege PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax CollegeCollege PhysicsPhysicsISBN:9781285737027Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning
- Physics for Scientists and Engineers, Technology ...PhysicsISBN:9781305116399Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning