A thin copper rod that is 1.0 m long and has a mass of 0.050 kg is in a magnetic field of 0.10 T. What minimum current in the rod is needed in order for the magnetic force to cancel the weight of the rod?

A) 1.2 A
B) 2.5 A
C) 4.9 A
D) 7.6 A
E) 9.8 A


Answer: C

Physics & Space Science

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: For a more precise lattice parameter, determine the lattice parameter from each of the peak intensities for tungsten in Figure 15.4. Then plot the value of a determined for each peak intensity as a function of the value of sin2 ? used to calculate a. The most accurate value of a results from extrapolation of sin2 ? to 1.0.

(a) Present your data table and plot. (b)What lattice parameter results?

Physics & Space Science

The inductance of a tuning circuit of an AM radio is 4.00 mH. Find the capacitance of the circuit required for reception at 1200 kHz.

A. 2.10 pF B. 4.40 pF C. 21.2 pF D. 43.4 pF E. 27.6 pF

Physics & Space Science

A person ties a rock to a string and whirls it around in a vertical circle such that sometimes the rock is going straight upward and sometimes the rock is going straight down

She whirls the rock at the minimum speed (constant in time) such that the string is always taut (no sag). If she were to use a longer string, she would have to whirl the rock at a A) higher velocity. B) lower velocity. C) the same velocity.

Physics & Space Science

An electron is placed in a uniform electric field of 4.5 × 104 N/C that points to the right. (e = 1.6 × 10-19 C, melectron = 9.11 × 10-31 kg)

(a) What are the magnitude and direction of the force on the electron? (b) If the electron is released from rest, what is its speed after 3.0 ps?

Physics & Space Science