Select the sentence that best describes why copper and some other metals are good conductors.

An electrically neutral atom has the same number of protons and electrons?

Which of the following is the best definition of an independent variable?

He output voltage and current of a transformer are determined by the

If predators are increased, then the cricket frog population will (increase/decrease/stay the same) over the span of five years.

Which of the following statements are true? (a) An object can move even when no force acts on it. (b) If an object isn't moving, no external forces act on it. (c) If a single force acts on an object, the object accelerates.

The graph shows that the molecules in a liquid do not all have the same speed

When the air under the envelope is heated, the balloon lifts. Which of the following statements is true?

A bullet of mass 6.00g is fired horizontally into a wooden block of mass 1.20kg resting on a horizontal surface. The coefficient of kinetic friction between block and surface is 0.160.

The graph represents the distance a car travels over time while on the highway. Which statement about the car's trip is accurate?

Energy conservation means a. slowing down a chemical change. b. burning a fuel to release energy. c. using fossil fuels to produce electricity. d. reducing energy use.