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