Why do scientists believe that dark matter exists even though it cannot be seen?

An electric current produces a magnetic field. a. True b. False

A cylinder has a height of 5.3 cm and a diameter of 3.0 cm. What is its volume? (Hint: Volume of a cylinder = min)

In any one material, all electromagnetic waves have the same a. wavelength. b. velocity. c. frequency. d. amplitude.

How would the force of a test charge change if the electric field is doubled? The force would double. The force would decrease by half. The force would increase by a factor of four. The force would decrease by a factor of four.

A 0.350kg leather wallet rests on top of an oak table. The force required to begin to move the wallet is 2.1N a) Determine the coefficient of static friction between the wallet and table.

A batter hits a baseball with a bat. The bat exerts a force on the ball. Does the ball exert a force on the bat?

In a nuclear power plant, the temperature of the water in the reactor is above 100°C because of what?

Determine the total mechanical energy of a 250 g baseball if it has a velocity of 30 m/s when it leaves the pitcher's hand 1.2m above the ground.

When distances were carefully measured from Earth to globular clusters above and below the Milky Way plane (where our view of them is not obscured by interstellar dust and gas), their distribution was found to be

Imagine you transfer heat into a gas. This heat splits up in two different ways: Additional thermal energy making the gas hotter and "fuel" for the gas to do work. Let's suppose, 64% of the transferred heat transforms into thermal energy.