Essential University Physics (3rd Edition)
3rd Edition
ISBN: 9780134202709
Author: Richard Wolfson
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Textbook Question
Chapter 7, Problem 52P
As an energy-efficiency consultant, you’re asked to assess a pumped-storage facility. Its reservoir sits 140 m above its generating station and holds 8.5 × 109 kg of water. The power plant generates 330 MW of electric power while draining the reservoir over an 8.0-h period. Its efficiency is the percentage of the stored potential energy that gets converted to electricity. What efficiency do you report?
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
The total consumption of electrical energy in the United States is about 1.0 1019 joules per year. What is the average rate of electrical energy consumption in watts? If the population of the United States is 300 million, what is the average rate of electrical energy consumption per person? The sun transfers energy to the earth by radiation at a rate of approximately 1.0 kW per square meter of surface. If this energy could be collected and converted to electrical energy with 40 % efficiency, how great an area (in square kilometers) would be required to collect the electrical energy used by the United States?
Please answer in 30 min! I will upvote!
A bucket full of sand has a mass of 20 kg (including the bucket and the sand). The bucket is to be lifted to
the top of a building 15 meters tall by a rope of negligible weight. However, the bucket has a hole in it, and
leaks 0.1 kgs of sand each meter it is lifted.
Find the work done lifting the bucket to the top of the building.
Hint: Force = (mass)(acceleration). For this problem, the force will be a product where a
m
9.8
82
Joules
Chapter 7 Solutions
Essential University Physics (3rd Edition)
Ch. 7.1 - Suppose it takes the same amount of work to push a...Ch. 7.2 - Gravitational force actually decreases with...Ch. 7.3 - A bowling ball is tied to the end of a long rope...Ch. 7.4 - For which of the following systems is (1)...Ch. 7.5 - A bowling ball is tied to the end of a long rope...Ch. 7.6 - The figure shows the potential energy associated...Ch. 7 - Figure 7.14 shows force vectors at different...Ch. 7 - Is the conservation-of-mechanical-energy principle...Ch. 7 - Why cant we define a potential energy associated...Ch. 7 - Can potential energy be negative? Can kinetic...
Ch. 7 - If the potential energy is zero at a given point,...Ch. 7 - If the difference in potential energy between two...Ch. 7 - If the difference in potential energy between two...Ch. 7 - A tightrope walker follows an essentially...Ch. 7 - If conservation of energy is a law of nature, why...Ch. 7 - Determine the work you would have to do to move a...Ch. 7 - Now lake Fig. 7.15 lo lie in a vertical plane, and...Ch. 7 - Rework Example 7.1, now taking the zero of...Ch. 7 - Find the potential energy associated with a 70-kg...Ch. 7 - You fly from Bostons Logan Airport, at sea level,...Ch. 7 - The potential energy associated with a 60-kg hiker...Ch. 7 - How much energy can be stored in a spring with k =...Ch. 7 - How far would you have to stretch a spring with k...Ch. 7 - A biophysicist grabs the ends of a DNA strand with...Ch. 7 - A skier starts down a frictionless 32 slope. After...Ch. 7 - A 10,000-kg Navy jet lands on an aircraft carrier...Ch. 7 - A 120-g arrow is shot vertically from a bow whose...Ch. 7 - In a railroad yard, a 35,000-kg boxcar moving at...Ch. 7 - You work for a toy company, and youre designing a...Ch. 7 - A 54-kg ice skater pushes off the wall of the...Ch. 7 - Prob. 25ECh. 7 - A particle slides along the frictionless track...Ch. 7 - A particle slides back and forth on a frictionless...Ch. 7 - A particle is trapped in a potential well...Ch. 7 - The reservoir at Northfield Mountain Pumped...Ch. 7 - The force in Fig. 7.14a is given by Fa=FoJ, where...Ch. 7 - A 1.50-kg brick measures 20.0 cm 8.00 cm 5.50...Ch. 7 - A carbon monoxide molecule can be modeled as a...Ch. 7 - A more accurate expression for the force law of...Ch. 7 - For small stretches, the Achilles tendon can be...Ch. 7 - The force exerted by an unusual spring when its...Ch. 7 - The force on a particle is given by F=Al/x2, where...Ch. 7 - A particle moves along the x-axis under the...Ch. 7 - As a highway engineer, youre asked to design a...Ch. 7 - A spring of constant k, compressed a distance x,...Ch. 7 - A child is on a swing whose 3.2-m-long chains make...Ch. 7 - With x x0 = h and a = g, Equation 2.11 gives the...Ch. 7 - The nuchal ligament is a cord-like structure that...Ch. 7 - A 200-g block slides back and forth on a...Ch. 7 - Automotive standards call for bumpers that sustain...Ch. 7 - A block slides on the frictionless loop-the-loop...Ch. 7 - The maximum speed of the pendulum bob in a...Ch. 7 - A mass m is dropped from height h above the top of...Ch. 7 - A particle with total energy 3.5 J is trapped in a...Ch. 7 - (a) Derive an expression for the potential energy...Ch. 7 - In ionic solids such as NaCl (salt), the potential...Ch. 7 - Repeat Exercise 19 for the case when the...Ch. 7 - As an energy-efficiency consultant, youre asked to...Ch. 7 - A spring of constant k = 340 N/m is used to launch...Ch. 7 - A bug slides back and forth in a bowl 15 cm deep,...Ch. 7 - A 190-g block is launched by compressing a spring...Ch. 7 - A block slides down a frictionless incline that...Ch. 7 - An 840-kg roller-coaster car is launched from a...Ch. 7 - A particle slides back and forth in a frictionless...Ch. 7 - A child sleds down a frictionless hill whose...Ch. 7 - A bug lands on top of the frictionless, spherical...Ch. 7 - A particle of mass m is subject to a force...Ch. 7 - A block of weight 4.5 N is launched up a 30...Ch. 7 - Your engineering department is asked to evaluate...Ch. 7 - Your roommate is writing a science fiction novel...Ch. 7 - You have a summer job at your universitys zoology...Ch. 7 - Biomechanical engineers developing artificial...Ch. 7 - Blocks with different masses are pushed against a...Ch. 7 - Nuclear fusion is the process that powers the Sun....Ch. 7 - Nuclear fusion is the process that powers the Sun....Ch. 7 - Nuclear fusion is the process that powers the Sun....Ch. 7 - Nuclear fusion is the process that powers the Sun....
Additional Science Textbook Solutions
Find more solutions based on key concepts
A uniform 40.0-kg scaffold of length 60 m is supported by tow light cables below. An 80.0 kg painter stands 1.0...
University Physics Volume 1
21. (II) (a) What is the electric potential 2.5 x 10-15m away from a proton (charge +e)? (b) What is the electr...
Physics: Principles with Applications
1. When is energy most evident?
Conceptual Physics (12th Edition)
Choose the best answer to each of the following. Explain your reasoning. What do we think resides in the center...
Cosmic Perspective Fundamentals
27. The electrical force that one electric charge exerts on another is proportional to the product of their cha...
College Physics
A 1.05-m-long rod of negligible weight is supported at its ends by wires A and B of equal length (Fig. P11.83)....
University Physics with Modern Physics (14th Edition)
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.Similar questions
- Sewage at a certain pumping station is raised vertically by 5.49 m at the rate of 1 890 000 liters each day. The sewage, of density 1 050 kg/m3, enters and leaves the pump at atmospheric pressure and through pipes of equal diameter. (a) Find the output mechanical power of the lift station. (b) Assume an electric motor continuously operating with average power 5.90 kW runs the pump. Find its efficiency.arrow_forwardSuppose that in one year a country produces 2.87×10112.87×1011 kilowatt‑hours (kWh)(kWh) of electrical energy from 41884188 hydroelectric plants (1.00 kWh=3.60×106 J).(1.00 kWh=3.60×106 J). On average, each plant is 90.0%90.0% efficient at converting mechanical energy to electrical energy, and the average dam height is 50.0 m.50.0 m. At 2.87×1011 kWh2.87×1011 kWh of electrical energy produced in one year, what is the average power output ?avgPavg per hydroelectric plant?arrow_forwardA 68 kg hiker walks at 5.0 km/h up a 4 % slope. The indicated incline is the ratio of the vertical distance and the horizontal distance expressed as percentage. What is the necessary metabolic power? Hint: You can model her power needs as the sum of the 380 W power to walk on level ground plus the power needed to raise her body by the appropriate amount. Assume that the efficiency of the body in using energy is 25%arrow_forward
- According to the World Energy Council, the average household in Mexico consumes about 1600 kWh of energy per year. In Monterrey, Nuevo León, Mexico, the GHI Solar Map suggests that the average annual solar energy potential is about 1800 kWh/m2 per year. If solar panels are available in sizes of 1 m × 1 m with an efficiency of 17%, how many panels will be needed to power a house in Monterrey for a year? Question 10 options: 6 7 2 1arrow_forwardb) A human can generate power of about 80 W. If one person works to raise water for 4 hours every day, what is the approximate volume of water that can be pumped from a 5 meter deep well in a month, assuming 50% efficiency? c) The water is to be used to irrigate a field of wheat, which requires a total of 15 cm depth of water over a three-month growing season. Using the answer from (b), how much area can be irrigated to a depth of 5 cm each month? d) If the yield of wheat is 0.1 kg/m², and the energy equivalent of wheat is 7.5 MJ/kg, what is the total energy produced by the field of wheat over a season? e) Assuming a food consumption per person of 10 MJ per day, how many person-days of food is generated by this field over a year?arrow_forwardAn energy storage system is being designed using a number of concrete blocks and electrically driven carriages, each carriage has a mass 10 000 kg, which can be raised to a certain height using electric motor driven trains using excess power from a combined solar-wind farm. Power is recovered using the same motors and releasing the concrete blocks and carriages. If the excess energy on one day is 2 GJ, the maximum height is 200 m and the efficiency is 100%, how many carriages are needed to store this energy (assume g = 10 m/s²). 4 B C O E 5 20 50 100 200arrow_forward
- A leaky 10-kg bucket is lifted from the ground to a height of 15 m at a constant speed with a rope that weighs 0.5 kg/m. Initially the bucket contains 45 kg of water, but the water leaks at a constant rate and finishes draining just as the bucket reaches the 15-m level. Find the work done. (Use 9.8 m/s2 for g.)arrow_forwardThe rectangular cistern (storage tank for rainwater) shown has its top 4 m below ground level. The cistern, currently full, is to be emptied for inspection by pumping its contents to ground level. Assume that the water weighs 9810 N/m³. Ground level 4 m 5 m 7m Complete parts (a) through (d) below. a. How much work will it take the empty the cistern? Set up an integral to find the work done. W = |9810(35)y dy How much work does it take to empty the tank? 8,240,400 joules (Round to the nearest integer as needed.) b. How long will it take a -hp pump, rated at 350 joules/sec to pump the tank dry? 392 min (Round to the nearest integer as needed.) c. How long will it take the pump in part (b) to empty the tank halfway? (It will be less than half the time required to empty the tank completely.) 164 min (Round to the nearest integer as needed.)arrow_forwardSuppose that in one year a country produces 2.77 × 10'' kilowatt-hours (kWh) of electrical energy from 4148 hydroelectric plants (1.00 kWh = 3.60 × 10° J). On average, each plant is 90.0% efficient at converting mechanical energy to electrical energy, and the average dam height is 50.0 m. At 2.77 x 10!1 kWh of electrical energy produced in one year, what is the average power output Payg per Pavg W %3D hydroelectric plant? What total mass of water m flowed over the dams during that year? m = kg What was the average mass of water mavg per dam that provided the mechanical energy to generate the electricity? mavg kg What was the average volume of water Vavg per dam that provided the mechanical energy to generate the electricity? (The density of water is 1000 kg/m³.) Vavg m %3D A gallon of gasoline contains 4.50 × 10' J of energy. How many gallons n of gasoline did the 4148 dams save? n = gal MacRook Proarrow_forward
- (a) What is the average power consumption in watts of an appliance that uses 5.93 kW · h of energy per day? Answer: ___________ W (b) How many joules of energy does this appliance consume in a year? Answer: ___________ Jarrow_forwardWater is pumped from a lake to a storage tank 25 m above at a rate of 70 L/s while consuming 22.4 kW of electric power. Disregarding any frictional losses in the pipes and any changes in kinetic energy, determine the overall efficiency of the pump–motor unit.arrow_forwardAssuming that the animal is at rest, its top speed is 32.7 meters per second (m/s). A cheetah's top speed can be calculated in terms of net work (in J). A food Calorie is equal to 4186 J. What is the cheetah's maximum net work calorie requirement? The amount calculated here is only a fraction of the energy that must be produced by the cheetah's body due to inefficiencies in converting chemical energy to mechanical energy.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- College PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax CollegePrinciples of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
College Physics
Physics
ISBN:9781938168000
Author:Paul Peter Urone, Roger Hinrichs
Publisher:OpenStax College
Principles of Physics: A Calculus-Based Text
Physics
ISBN:9781133104261
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Mechanical work done (GCSE Physics); Author: Dr de Bruin's Classroom;https://www.youtube.com/watch?v=OapgRhYDMvw;License: Standard YouTube License, CC-BY