A single atom of an element has 21 neutrons, 20 electrons, and 20 protons. Which element is it?

What makes comets different from asteroids and meteoroids? Question 8 options: A. They don't consist of ice. B. They travel in space. C. They consist of ice. D. They fly.

The unique sound quality of a clarinet or a violin is caused by the

What happens if you stick a charged balloon to a metal object?

What is a half-life the reactive half of a radioactive substance the amount of time it takes for all of a radioactive substance to decay the amount of time it takes for half of a radioactive substancec to decay half the time it takes for a

Potential energy: Select one: a. is stored energy unavailable to do work. b. transfers motion to matter. c. is contained in matter placed in certain positions or arrangements. d. contains less energy than kinetic energy. e.

What is the momentum of a 15 kg tire rolling down a hill at 3 m/s? 5 kg • m/s 18 kg • m/s 45 kg • m/s 60 kg • m/s

Which of Newton's laws, when combined algebraically with his law of universal gravitation, can be used to calculate Earth's mass? A) first B) second C) third

Why does a balloon filled with helium rise while a balloon filled with an equal volume of average atmospheric air does not? A. Helium has no mass, but air does. B. Helium increases the balloon's mass more than air. C.

Consider the following controls in an automobile in motion : gas pedal, brake, steering wheel. what are the controls in this list that cause an acceleration of the car?

What material are oil pipelines made from?