Questions from College Physics

Q: Why is the speed of sound in solids generally much faster than

Why is the speed of sound in solids generally much faster than the speed of sound in air?

Q: A magnet produces a 0.30 T field between its poles

A magnet produces a 0.30 T field between its poles, directed to the east. A dust particle with charge q = −8.0 × 10−18 C is moving straight down at 0.30 cm/s in this field. What is the magnitude and d...

Q: At a certain point on Earth's surface in the southern hemisphere,

At a certain point on Earth's surface in the southern hemisphere, the magnetic field has a magnitude of 5.0 × 10−5 T and points upward and toward the north at an angle of 55° above the horizontal. A c...

Q: The energy at which the fundamental forces are expected to unify is

The energy at which the fundamental forces are expected to unify is about 1019 GeV. Find the mass (in SI units) of a particle with rest energy 1019 GeV.

Q: A variable inductor can be placed in series with a lightbulb to

A variable inductor can be placed in series with a lightbulb to act as a dimmer. (a) What inductance would reduce the current through a 100 W lightbulb to 75% of its maximum value? Assume a 120 V rms...

Q: (a) Show that the number of electron states in a

(a) Show that the number of electron states in a sub-shell is 4â„“ + 2. [Hint: First, how many states are in each orbital? Second, how many orbitals are in each subshell?] (b) By summ...

Q: Common sports injuries result in the tearing of tendons and ligaments due

Common sports injuries result in the tearing of tendons and ligaments due to overstretching. If the anterior cruciate ligament (ACL) in an athlete’s knee has a length of 1.0 cm, a breaking point of 19...

Q: A sample of gold, / , decays radioactively with

A sample of gold, , decays radioactively with an initial rate of 1.00 × 1010 Bq into / . The half-life is 2.70 days. (a) What is the decay rate after 8.10 days? (b) What particle or p...

Q: A 100 g ball collides elastically with a 300 g ball that

A 100 g ball collides elastically with a 300 g ball that is at rest. If the 100 g ball was traveling in the positive x-direction at 5.00 m/s before the collision, what are the velocities of the two ba...

Q: A cosmic ray muon with the same charge as an electron and

A cosmic ray muon with the same charge as an electron and a mass of 1.9 × 10−28 kg is moving toward the ground at an angle of 25° from the vertical with a spe...