In an equal-arm balance from the early 20th century (Fig. 31.23), an aluminum sheet hangs from one of the arms and passes between the poles of a magnet, causing the oscillations of the balance to decay rapidly. In the absence of such magnetic braking, the oscillation might continue for a long time, and the experimenter would have to wait to take a reading. Why do the oscillations decay? (a) because the aluminum sheet is attracted to the magnet (b) because currents in the aluminum sheet set up a magnetic field that opposes the oscillations (c) because aluminum is paramagnetic
Figure 31.23 (Quick Quiz 31.5) In an old-fashioned equal-arm balance, an aluminum sheet hangs between the poles of a magnet.
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Chapter 31 Solutions
EBK PHYSICS FOR SCIENTISTS AND ENGINEER
- Water flowing from an oscillating sprinkler head produces a velocity fieldgiven by~v = u0 sin[ω(t −y/v0)]ˆi + v0ˆj.where u0, v0 and ω are constants (which you are free to assign and experi-ment with). Thus, the y component of velocity remains constant (vy= v0)and the x component of velocity at y = 0 coincides with the velocity of theoscillating sprinkler head [vx= u0 sin(ωt) at y = 0].(a) Write a program to plot the velocity field and a few streamlines for afixed value of t. Include the capability of varying t in the streamlinesand velocity field plot.(b) On a separate figure plot a few pathlines of particles which emergefrom the point (0,0) at some time prior to time t and the correspondingstreakline at time t.(c) Describe the pathlines and streakline for this flow.arrow_forwardSolve the equations 1/2 mv^2 + 1/2 Iω^2 = mgh and v = rω for the speed v using substitution, given that I = mr^2 and h = 3.76 m. (Note that mass m and radius r will both cancel, so their numerical values aren't required.)arrow_forwardA 5.04-kg object oscillates back and forth at the end of a spring whose spring constant is 67.3 N/m. An observer is traveling at a speed of 2.36 × 108 m/s relative to the fixed end of the spring. What does this observer measure for the period of oscillation? Number Unitsarrow_forward
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- An X-ray machine makes an image of the internal organs by exposing the human body to the electromagnetic radiation with the wavelength of 10^-10 m. We call this electromagnetic radiation X-rays. Assuming that the speed of light is 3x10^8 m/s, what is the frequency of oscillations of the X-rays? Express your answer in Hertz (Hz).arrow_forwardA carriage runs along rails on a rigid beam. The carriage is attached to one end of a spring of equilibrium length r0 and force constant k, whose other end is fixed on the beam. On the carriage, another set of rails is perpendicular to the first along which a particle of mass m moves, held by a spring fixed on the beam, of force constant k and zero equilibrium length. Beam, rails, springs, and carriage are assumed to have zero mass. The whole system is forced to move in a plane about the point of attachment of the first spring, with a constant angular speed ω. The length of the second spring is at all times considered small compared to r0. What is the energy of the system? Is it conserved?arrow_forwardA carriage runs along rails on a rigid beam. The carriage is attached to one end of a spring of equilibrium length r0 and force constant k, whose other end is fixed on the beam. On the carriage, another set of rails is perpendicular to the first along which a particle of mass m moves, held by a spring fixed on the beam, of force constant k and zero equilibrium length. Beam, rails, springs, and carriage are assumed to have zero mass. The whole system is forced to move in a plane about the point of attachment of the first spring, with a constant angular speed ω. The length of the second spring is at all times considered small compared to r0. Using generalized coordinates in the laboratory system, what is the Jacobi integral for the system? Is it conserved?arrow_forward
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