
Concept explainers
Flywheels are large, massive wheels used to store energy. They can be spun up slowly, then the wheel’s energy can be released quickly to accomplish a task that demands high power. An industrial flywheel has a 1.5 m diameter and a mass of 250 kg. Its maximum
a. A motor spins up the flywheel with a constant torque of 50 N m. How long does ii take the flywheel to reach top speed?
b. How much energy is stored in the flywheel?
c. The flywheel is disconnected from the motor and connected to a machine to which it will deliver energy. Half the energy stored in the flywheel is delivered in 2.0 s. What is the average power delivered to the machine?
d. How much torque does the flywheel exert on the machine?

Want to see the full answer?
Check out a sample textbook solution
Chapter 12 Solutions
Student Workbook for Physics for Scientists and Engineers: A Strategic Approach, Vol 1. (Chs 1-21)
- 3.) The graph shows how current I varies with potential difference V across a component X. 904 80- 70- 60- 50- I/MA 40- 30- 20- 10- 0+ 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 VIV Component X and a cell of negligible internal resistance are placed in a circuit. A variable resistor R is connected in series with component X. The ammeter reads 20mA. 4.0V 4.0V Component X and the cell are now placed in a potential divider circuit. (a) Outline why component X is considered non-ohmic. [1] (b(i)) Determine the resistance of the variable resistor. [3] (b(ii)) Calculate the power dissipated in the circuit. [1] (c(i)) State the range of current that the ammeter can measure as the slider S of the potential divider is moved from Q to P. [1] (c(ii)) Describe, by reference to your answer for (c)(i), the advantage of the potential divider arrangement over the arrangement in (b).arrow_forward1.) Two long parallel current-carrying wires P and Q are separated by 0.10 m. The current in wire P is 5.0 A. The magnetic force on a length of 0.50 m of wire P due to the current in wire Q is 2.0 × 10-s N. (a) State and explain the magnitude of the force on a length of 0.50 m of wire Q due to the current in P. [2] (b) Calculate the current in wire Q. [2] (c) Another current-carrying wire R is placed parallel to wires P and Q and halfway between them as shown. wire P wire R wire Q 0.05 m 0.05 m The net magnetic force on wire Q is now zero. (c.i) State the direction of the current in R, relative to the current in P.[1] (c.ii) Deduce the current in R. [2]arrow_forward2.) A 50.0 resistor is connected to a cell of emf 3.00 V. The voltmeter and the ammeter in the circuit are ideal. V A 50.00 (a) The current in the ammeter is 59.0 mA. Calculate the internal resistance of the cell. The circuit is changed by connecting another resistor R in parallel to the 50.0 resistor. V A 50.00 R (b) Explain the effect of this change on R is made of a resistive wire of uniform cross-sectional area 3.1 × 10-8 m², resistivity 4.9 × 10-70m and length L. The resistance of R is given by the equation R = KL where k is a constant. (b.i) the reading of the ammeter. [2] (b.ii) the reading of the voltmeter. [2] (c) Calculate k. State an appropriate unit for your answer. [3] [2]arrow_forward
- No chatgpt pls will upvotearrow_forwardNo chatgpt pls will upvotearrow_forwardA rod 12.0 cm long is uniformly charged and has a total charge of -20.0 μc. Determine the magnitude and direction of the electric field along the axis of the rod at a point 32.0 cm from its center. 361000 ☑ magnitude What is the general expression for the electric field along the axis of a uniform rod? N/C direction toward the rodarrow_forward
- A certain brand of freezer is advertised to use 730 kW h of energy per year. Part A Assuming the freezer operates for 5 hours each day, how much power does it require while operating? Express your answer in watts. ΜΕ ΑΣΦ ? P Submit Request Answer Part B W If the freezer keeps its interior at a temperature of -6.0° C in a 20.0° C room, what is its theoretical maximum performance coefficient? Enter your answer numerically. K = ΜΕ ΑΣΦ Submit Request Answer Part C What is the theoretical maximum amount of ice this freezer could make in an hour, starting with water at 20.0°C? Express your answer in kilograms. m = Ο ΑΣΦ kgarrow_forwardDescribe the development of rational choice theory in sociology. Please includearrow_forwardA-E pleasearrow_forward
- A 11.8 L gas tank containing 3.90 moles of ideal He gas at 26.0°C is placed inside a completely evacuated insulated bell jar of volume 39.0 L .A small hole in the tank allows the He to leak out into the jar until the gas reaches a final equilibrium state with no more leakage. Part A What is the change in entropy of this system due to the leaking of the gas? ■ ΜΕ ΑΣΦ AS = ? J/K Submit Request Answer Part B Is the process reversible or irreversible?arrow_forwardA-E pleasearrow_forwardThree moles of an ideal gas undergo a reversible isothermal compression at 20.0° C. During this compression, 1900 J of work is done on the gas. For related problem-solving tips and strategies, you may want to view a Video Tutor Solution of Entropy change in a free expansion. Part A What is the change of entropy of the gas? ΤΕ ΑΣΦ AS = Submit Request Answer J/Karrow_forward
- University Physics Volume 1PhysicsISBN:9781938168277Author:William Moebs, Samuel J. Ling, Jeff SannyPublisher:OpenStax - Rice UniversityGlencoe Physics: Principles and Problems, Student...PhysicsISBN:9780078807213Author:Paul W. ZitzewitzPublisher:Glencoe/McGraw-HillPhysics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning
- College PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax CollegeCollege PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage LearningPrinciples of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning





