Which of the following is made from a Crystaline solid that conducts a current only under certain circumstances?

•vacuum tube

•cathode-ray tube

•analog device

•semiconductor

Energy released by fusion in the sun is initially in the form of

A runner covers the last straigjt stretch of a race in 4 s. during that time, he speeds up from 5m/s to 9m/s.

A vehicle's oil pressure warning light is on. Technician A says that the pressure sending unit should be replaced and the vehicle re-checked.

Suppose a 50-turn coil lies in the plane of the page in a uniform magnetic field that is directed into the page. The coil originally has an area of 0.250m2. It is stretched to have no area in 0.100 s.

Assume you are a fish in fresh water. you get up every morning and weigh yourself on your scales, and find you weigh 0.420 n. you, being a boxfish, are a box measuring 4.174 cm per side. you see a poor, hungry fisherman, and decide to be his dinner.

According to the kinetic theory of gases, the kinetic energy of molecules is proportional to which factor? A. Concentration in moles/liters B. temperature in kelvin

A large container of water is sitting on a balance. The weight of the container plus the water is 10 newtons. An object the weight of 7 newtons hanging from a forcemeter is lowered towards the surface of the water.

Which of the following could you do to increase the strength of an electromagnet?

A car accelerates from 13 m s to 25 m s in 6.0 s. what was its acceleration? how far did it travel in this time? assume constant acceleration.

How much elastic potential energy is stored in a bungee cord with a spring constant of 10.0 N/m when the cord is stretched 2.00 m?