Concept explainers
You are part of a team working in a machine parts mechanic’s shop. An important customer has asked your company to provide springs with a very precise force constant k. To measure the spring constant, you fasten two of the springs between the ends of two very long wires of length L, separated by the unstretched length ℓ of the springs as shown in Figure P29.15. The specific attachment method that you use insulates the springs from the wires so that no current passes through the springs. You lay the apparatus flat on a table and then pass a current of magnitude I through the wires, in opposite directions. As a result the springs stretch by a distance d and come to equilibrium. You determine an expression for the spring constant in terms of L, I, ℓ, and d.
Figure P29.15
Trending nowThis is a popular solution!
Chapter 29 Solutions
Physics for Scientists and Engineers
- 6.11 The loop shown in P6.11 moves away from a wire carrying a current I1 = 10 A at a constant velocity u = §7.5 (m/s). If R = 10 N and the direction of I2 is as defined in the figure, find I2 as a function of yo, the distance between the wire and the loop. Ignore the internal resistance of the loop. 10 cm I1 = 10 A 20 cm Уoarrow_forwardCan you please answer d, e?arrow_forwardTwo very long, parallel wires are separated by d = 0.065 m. The first wire carries a current of I1 = 0.75 A. The second wire carries a current of I2 = 0.65 A. Express the minimal work per unit length needed to separate the two wires from d to 2d.arrow_forward
- QI. A capacitor consists of two circular plates of radius a separated by a distance d (assume d a. (A) Use Gauss' Law to find the electric field between the plates as a function of time t, in terms of q(1), a, ɛ, and z. The vertical direction is the k direction. (B)Now take an imaginary flat disc of radius rarrow_forwardA coil is constructed by wrapping a wire of length 8.6 on a paper cylinder of radius 0.03 m and length 0.10 m. A current of 0.1 A is applied to coil. What is the expected value of the field at the center of the coil? Hint: determine the number of turns of wire that fit the cylinder and determine the number of turns per unit of cylinder length. Answer in microTesla (1 microTesla= 106 Tesla).arrow_forward(a) What is the average power output of a heart defibrillator that dissipates 400 J of energy in 10.0 ms? (b) Considering the high-power output, why doesn’t the defibrillator produce serious bums?arrow_forwardA resistor R is connected between two parallel conducting rails separated by 30 cm, as shown in the diagram. A conducting bar maintains electric contact with the rails as it moves relative to them with constant velocity from x = 20 cm to x = 48 cm in 0.6 seconds. A uniform 0.8 T field points into the page. Calculate the induced electric potential difference between the two ends of the bar.arrow_forwardTwo resistanceless rails rest 42 cm apart on a 6.6o ramp. They are joined at the bottom by a 0.68 Ω resistor. At the top, a copper bar of mass 0.034 kg (ignore its resistance) is laid across the rails. The whole apparatus is immersed in a vertical 0.35 T field. What is the terminal (steady) velocity of the bar as it slides frictionlessly down the rails?arrow_forwardA rail gun uses electromagnetic forces to accelerate a projectile to very high velocities. The basic mechanism of acceleration is relatively simple and can be illustrated in the following example. A metal rod of mass 40.0 g and electrical resistance 0.300 Ω rests on parallel horizontal rails that have negligible electric resistance. The rails are a distance L = 9.00 cm apart. (Figure 1)The rails are also connected to a voltage source providing a voltage of V = 5.00 V .The rod is placed in a vertical magnetic field. The rod begins to slide when the field reaches the value B = 0.131 T . Assume that the rod has a slightly flattened bottom so that it slides instead of rolling. Use 9.80 m/s^2 for the magnitude of the acceleration due to gravity. A) Find μ_s, the coefficient of static friction between the rod and the rails. Give the answer numericallyarrow_forwardQuestion: V Figure 1. A rectangular sample of semiconductor is in a magnetic field B, oriented approximately into the page, as shown. The sample is connected to an ammeter, voltmeter and a voltage source. The schematic shows a circuit involving a sample of semiconductor, whose cross-section is L by w. The sketch is not to scale and the electrodes attached to the sample are not shown. A uniform magnetic field B is applied in the direction indicated by the crosses (roughly, into the page). Each charge carrier has a charge q and the density of charge carriers, measured in ions per cubic metre, is n. Part 1) Use the definition of electric current to give an expression for the average speed of the charge carriers when the ammeter registers a current i. vd = Part 2) Give an expression for the magnitude of the magnetic force on a charge carrier. Your answer should be in terms of ¿, not v. F= Part 3) The magnetic force in part 2 produces a lateral displacement in the charge carriers, and the…arrow_forwardA biophysics experiment uses a very sensitive magnetic field probe to determine the current associated with a nerve impulse traveling along an axon. If the peak field strength 1.0 mm from an axon is 8.0 pT, what is the peak current carried by the axon?arrow_forwardarrow_back_iosSEE MORE QUESTIONSarrow_forward_iosRecommended textbooks for you
- Physics for Scientists and EngineersPhysicsISBN:9781337553278Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning
Physics for Scientists and EngineersPhysicsISBN:9781337553278Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning