Which of the following is a source of direct electric current?

A. transformer

B. Coulomb

C. switch

D. battery

A heavy rope, 50 ft long, weighs 0.5 lb/ft and hangs over the edge of a building 120 ft high. how much work is done (in ft-lb) in pulling half the rope to the top of the building?

What is the process in which a nucleus of an atom breaks up, emitting subatomic particles and/or energy?

Walking without slipping requires a static friction force between your feet (or footwear) and the floor.

Explain the advantages and disadvantages of using concentric circles in describing the solar system to an elementary school child.

Because of the curvature of the earth, the maximum distance D that you can see from the top of a tall building of height h is estimated by the formula D = 2rh + h2 where r = 3960 mi is the radius of the earth and D and h are also measured in miles.

How do most primary producers make their own food?

The maximum kinetic energy of photoelectrons is 3.10 ev. when the wavelength of the light is increased by 50%, the maximum energy decreases to 1.50 ev. part a what is the work function of the cathode?

Which of the following most completely describes an objects motion? A. a car travels 25 miles. B. The baby crawls 10 feet in 15 seconds toward the door. C. A marble rolls 10 m to the left D. The rain falls at a rate of one inch per hour

Why is the use of carbon-14 limited

Why do cell sometimes need to use active transport?