Questions from College Physics

Q: A charged parallel plate capacitor has the space between the plates filled

A charged parallel plate capacitor has the space between the plates filled with air. The capacitor has been disconnected from the battery that charged it. Describe quantitatively what happens to the c...

Q: A bird is perched on a high-voltage power line whose

A bird is perched on a high-voltage power line whose potential varies between −100 kV and +100 kV. Why is the bird not electrocuted?

Q: An African swallow carrying a very small coconut is flying horizontally with

An African swallow carrying a very small coconut is flying horizontally with a speed of 18 m/s. (a) If it drops the coconut from a height of 10 m above Earth, how long will it take before the coconut...

Q: A solid copper disk of radius R rotates at angular velocity ω

A solid copper disk of radius R rotates at angular velocity ω in a perpendicular magnetic field B. The figure shows the disk rotating clockwise and the magnetic field into the page. (a) Is...

Q: A man requires reading glasses with +2.0 D refractive

A man requires reading glasses with +2.0 D refractive power to read a book held 40.0 cm away with a relaxed eye. Assume the glasses are 2.0 cm from his eyes. (a) What is his uncorrected far point? (...

Q: The graph shows x(t) for an object traveling along

The graph shows x(t) for an object traveling along the x-axis. Plot vx as a function of time for this object from t = 0 to t = 8 s.

Q: A parallel plate capacitor has a capacitance of 1.20 nF

A parallel plate capacitor has a capacitance of 1.20 nF. There is a charge of 0.80 µC on each plate. How much work must be done by an external agent to double the plate separation while keeping the ch...

Q: A hot air balloon is floating in equilibrium with the surrounding air

A hot air balloon is floating in equilibrium with the surrounding air. (a) How does the pressure inside the balloon compare with the pressure outside? (b) How does the density of the air inside compa...

Q: For an ideal inductor in an ac circuit, explain why the

For an ideal inductor in an ac circuit, explain why the voltage across the inductor must be zero when the current is maximum.

Q: A star is moving away from Earth at a speed of 2

A star is moving away from Earth at a speed of 2.4 × 108 m/s. Light of wavelength 480 nm is emitted by the star. What is the wavelength as measured by an Earth observer?