A machine is supplied energy at a rate of 4000 watts and does useful work at a rate of 3761 watts what

is the efficiency of the machine

What is the electric potential energy of an electron at the negative end of the cable, relative to the positive end of the cable?

A car starts from rest at a stop sign. It accelerates at 4.0 m/s2 for 3 seconds, coasts for 2 s, and then slows down at a rate of 3.0 m/s2 for the next stop sign. How far apart are the stop signs?

Part A The major axis for a particular planet is known. In order to determine the perihelion and the aphelion, what other information about the planet is needed? 1. The mass of the planet 2. The orbital period 3. The eccentricity of the orbit

As a blacksmith heats a piece of iron, the iron glows red, then yellow, then white. The iron provides a demonstration of which phenomenon? A. Emission spectra B. Quantum mechanics C. Photoelectric effect D. Blackbody radiation

All the following statements are true. Which one is most important in explaining the tremendous tidal heating that occurs on Io?

A wave with a frequency of 30 Hz has a wavelength of 40.5 m. How fast is the wave traveling?

A soccer ball is sitting in the middle of a soccer field during a game. When the referee blows his whistle, one of the players runs toward the ball and kicks it as hard as he can.

A body with v=20m/s changes its speed to 28m/s in 2sec. its acceleration will be

Charge: A piece of plastic has a net charge of + 2.00 μC. How many more protons than electrons does this piece of plastic have? (e = 1.60 * 10-19 C)

How much heat is needed to raise the temperature of 6g of water by 18oC?