An electric current that changes directions at regular intervals is called

a. directional current.

c. reversible current.

b. alternating current.

d. fluctuating current.

Draw a distance over time graph of a dog that is tied to a 4 foot rope and travels in 1 complete circle

A rocket is launched straight up with constant acceleration. Four seconds after liftoff, a bolt falls off the side of the rocket. The bolt hits the ground 6.0 s later. What was the rocket's acceleration?

Explain what the ionosphere is and how it interacts with some radio waves.

In the diagram above (not to scale), Vx/y = 12.57 meters/second and Vy/z = 5.21 meters/second. What is the value of the resultant vector?

A cathode-ray tube (CRT) is an evacuated glass tube. Electrons are produced at one end, usually by the heating of a metal.

Are microwaves and radio waves faster or slower than other types of electromagnetic energy?

If you dive under-water, you notice an uncomfortable pressure on your eardrums due to the increased pressure. The human eardrum has an area of about 70 mm2 (7*10-5m2), and it can sustain a force of about 7 N without rupturing.

Why cant kinetic energy ever be greater than potential energy

For a stationary observer, when the source of a sound is moving, its pitch appears to change.

Give an example of each simple machine