Questions from College Physics

Q: Credit cards have a magnetic strip that encodes information about the credit

Credit cards have a magnetic strip that encodes information about the credit card account. Why do devices that read the magnetic strip often include the instruction to swipe the card rapidly? Why can’...

Q: A helicopter is lifting two crates simultaneously. One crate with a

A helicopter is lifting two crates simultaneously. One crate with a mass of 200 kg is attached to the helicopter by a cable. The second crate with a mass of 100 kg is hanging below the first crate and...

Q: Consider two protons (charge +e), separated by a distance

Consider two protons (charge +e), separated by a distance of 2.0 × 10−15 m (as in a typical atomic nucleus). The electric force between these protons is equal in magnitude to the gravitational force o...

Q: Earth’s orbit around the Sun is nearly circular. The period is

Earth’s orbit around the Sun is nearly circular. The period is 1 yr = 365.25 d. (a) In an elapsed time of 1 d, what is Earth’s angular displacement in radians? (b) What is the change in Earth’s velo...

Q: A small object of mass 0.50 kg is attached by

A small object of mass 0.50 kg is attached by a 0.50 m long cord to a pin set into the surface of a frictionless table top. The object moves in a circle on the horizontal surface with a speed of 2.0π...

Q: Three capacitors (2.0 µF, 3.0 µF

Three capacitors (2.0 µF, 3.0 µF, 6.0 µF) are connected in series to an ac voltage source with amplitude 12.0 V and frequency 6.3 kHz. (a) What are the peak voltages across each capacitor? (b) What...

Q: (a) What is the reactance of a 10.0

(a) What is the reactance of a 10.0 mH inductor at the frequency f = 250.0 Hz? (b) What is the impedance of a series combination of the 10.0 mH inductor and a 10.0 Ω resistor at 250.0 Hz? (c) What i...

Q: Two different monochromatic light sources, one yellow (580 nm)

Two different monochromatic light sources, one yellow (580 nm) and one violet (425 nm), are used in a photoelectric effect experiment. The metal surface has a photoelectric threshold frequency of 6.20...

Q: The magnetic field between the poles of a magnet has magnitude 0

The magnetic field between the poles of a magnet has magnitude 0.55 T. A circular loop of wire with radius 3.2 cm is placed between the poles so the field makes an angle of 22° with the plane of the l...

Q: An airplane of mass 2800 kg has just lifted off the runway

An airplane of mass 2800 kg has just lifted off the runway. It is gaining altitude at a constant 2.3 m/s while the horizontal component of its velocity is increasing at a rate of 0.86 m/s2. Assume g =...