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

A stone is thrown upward from ground level. With what minimum speed should the stone be thrown so as to reach a height of 100 feet? ... ?

a motorcyclist sees a branch in the road and hits the brakes, slowing down at - 6.42 m/s. if it takes him 2.85 us to stop, what was his starting velocity

An object initially at rest experiences an acceleration of 0.281 m/s2 to the South for a time of 5.44 seconds. It then increases its acceleration to 1.43 m/s2 to the South for an additional 2.42 seconds.

A powered winch is used to pull a sailboat to shore. The winch uses a 900 W motor. If the motor is used for 30 s, how much work does it do? (Power: P = W/t)

If the power goes out, so that the wheel's motor no longer provides any torque, how long will it take the wheel to come to a stop?

The index of refraction of silicate flint glass for red light is 1.620 and for violet light is 1.660. A beam of white light in this glass strikes the glass-air interface at a 25.50∘ angle of incidence and refracts out into the air.

The locations of the major pressure and wind systems on the earth:

Which statements correctly describe the properties of heat? Select all that apply. Heat is an essential component of life on Earth. Heat is energy that flows from one object to another. Heat flows from a hotter object to a colder one.

A book is sitting on a table at rest. Which of the following best describes the forces acting on the book? A.

When NASA's Skylab reentered the Earth's atmosphere on July 11, 1979, it broke into a myriad of pieces. One of the largest fragments was a 1770-kg lead-lined film vault, and it landed with an estimated speed of 120 m/s.?