The atomic number of an element is 19. Which is true of this element?

A.

Each atom has an atomic mass of 19.

B.

Each atom has 19 neutrons.

C.

Each atom has 19 protons.

D.

Each atom forms 19 ions.

A horizontal uniform board of weight 125N and length 4 m is supported by vertical chains at each end. A person weighing 500N sitting on the board. Thr tension in the right chain is 250N. How far from left of the end person is sitting

What produces the force for the torque that turns an electric motor? The electrical attraction of opposite charges. The force on a current in a magnetic field. An induced electromotive force acting on a loop of wire.

A person of 83 kg is in an elevator. If the elevator is moving at a speed of 5 m/s, what's the person's kinetic energy? Keep 4 significant figures a 1,004 J b 1,038 c 1,280 J d 980 J e 1,435 J

Which substance has the most thermal energy and will have the most heat flow from it? a stovetop burner on medium (200°C) a nuclear reactor core (1000°C) the human body (36°C) air at room temperature (32°C)

How many significant figures is in 15,600

A 20kg box is dropped 13m. how much work is done

Suppose a person whose mass is m is being held up against the wall with a constant tangential velocity v greater than the minimum necessary. Find the magnitude of the frictional force between the person and the wall

A ball is being rolled by a normal push of 1000N. it is opposed by friction which has a force of 0.3kN and air resistance which has a force of 23N. Calculate the resultant force.

Consider a Young's two-slit experiment in which the wavelength of light is 37% smaller than the distance between the slits.

Which of the following situations would produce an average velocity of zero? A) a round-trip to school and back B) a horse galloping in a field C) the criss-crossing path of a flying bug D) a trip, first to the moon, then onto Mars