Across
- 1. the SI unit of length
- 3. a measure of the amount of matter in an object
- 4. when the only force acting on an object is gravity
- 8. the steepness of a line on a graph
- 11. the distance an object travels per unit of time
- 12. the tendency of an object to resist a change in motion
- 13. a force that pulls objects toward each other
- 16. energy an object has because of its position
- 17. the force of gravity on a person or object at the surface of a planet
- 19. an atom with an electric charge
- 20. empty space
- 22. a push or a pull
- 23. a substance that freely flows
- 24. a measure of the average energy or random motion of particles of matter
- 26. atoms with the same number of protons but different numbers of neutrons
- 27. the combination of forces acting on an object
- 30. a place or object used for comparison to determine if something is in motion
- 32. a rapid reaction between oxygen and a fuel
Down
- 2. the greatest speed a falling object reaches, when air resistance equals the weight of the object
- 5. a form of energy that travels through space as waves
- 6. anything that has mass and takes up space
- 7. the spontaneous emission of radiation by an unstable atomic nucleus
- 9. a pure substance that cannot be broken down into any other substances by chemical or physical means
- 10. the SI unit of force
- 14. mass the average mass of all the isotopes of an element
- 15. the rate at which velocity changes
- 18. a type of fluid friction objects experience when falling through an atmosphere
- 20. speed in a given direction
- 21. the study of the properties of matter and how matter changes
- 25. the amount of a substance in a given volume
- 28. energy of matter in motion
- 29. an object is in ______ if it changes position relative to a reference point
- 31. the force that two surfaces exert on each other when they rub against each other