Carlota does 2000 J of work on a machine. The machine does 500 J of work. What is the efficiency of the machine?

A. 4%

B. 25%

C. 75%

D. 400%

A hydroelectric plant takes energy from water and turns it into electrical energy. What are the transformations of energy in the water molecules that are used in the process of generating electricity this way?

How can a magnetic field be used to generate an electric current? A. Electric current flows when a stationary magnet causes the magnetic field to change. B. Electrons in a wire flow when a stationary magnet causes the electrical field to change. C.

What 2 characteristics of stars are shown in an H-R diagram?

It takes a wave traveling on a string 1.2 s to complete a full cycle. You measure the distance it takes to repeat itself to be 1.8 m. How fast is the wave moving?

A straight wire carrying a 3.30-A current is placed in a uniform magnetic field of magnitude 0.272 T directed perpendicular to the wire. (a) Find the magnitude of the magnetic force on a section of the wire having a length of 12.7 cm.

According to the Big Bang theory timeline, all matter and energy was compressed into a very small volume at an extremely high temperature. a. True b. False

Sal is thinking about making a positive change in his life. But there are risks involved. Which is the healthiest way that Sal can approach these risks?

The push of energy given to electrons in a circuit is known as what?

How many calories would you burn if you walked for 120 minutes at a pace of 3-mph?

What force oppose other forces and slow objects down?