Questions from College Physics

Q: What happens if a 40 W incandescent lightbulb, designed to be

What happens if a 40 W incandescent lightbulb, designed to be connected to an ac voltage with amplitude 170 V and frequency 60 Hz, is instead connected to a 170 V dc power supply? Explain. What dc vol...

Q: A concave mirror has focal length f. (a)

A concave mirror has focal length f. (a) If you look into the mirror from a distance less than f, is the image you see upright or inverted? (b) If you stand at a distance greater than 2f, is the imag...

Q: The time to sunset can be estimated by holding out your arm

The time to sunset can be estimated by holding out your arm with your fingers perpendicular to the path the Sun will follow to the horizon. The number of fingers that fit between the Sun and the sunse...

Q: An object has a mass of 12.6 kg and a

An object has a mass of 12.6 kg and a speed of 0.87c. (a) What is the magnitude of its momentum? (b) If a constant force of 424.6 N acts in the direction opposite to the object's motion, how long mu...

Q: A rod is negatively charged by rubbing it with fur. It

A rod is negatively charged by rubbing it with fur. It is brought near another rod of unknown composition and charge. There is a repulsive force on each. (a) Is the first rod an insulator or a conduc...

Q: Suppose that as you travel away from Earth in a spaceship,

Suppose that as you travel away from Earth in a spaceship, you observe another ship pass you heading in the same direction and measure its speed to be 0.50c. As you look back at Earth, you measure Ear...

Q: Crocodiles are thought to be able to detect changes in the flux

Crocodiles are thought to be able to detect changes in the flux due to Earth’s magnetic field as they move their heads. Suppose a crocodile is initially facing north. The horizontal component of Earth...

Q: Suppose that a string of length L and mass m is under

Suppose that a string of length L and mass m is under tension F. (a) Show that has units of speed. (b) Show that there is no other combination of L, m, and F with units of speed. [Hint: Of the dim...

Q: A spring scale in a French market is calibrated to show the

A spring scale in a French market is calibrated to show the mass of vegetables in grams and kilograms. (a) If the marks on the scale are 1.0 mm apart for every 25 g, what maximum extension of the spr...

Q: Many real estate agents have an ultrasonic rangefinder that enables them to

Many real estate agents have an ultrasonic rangefinder that enables them to quickly and easily measure the dimensions of a room. The device is held to one wall and reads the distance to the opposite w...