Across
- 4. a decrease in velocity over time
- 6. the rate of change of velocity
- 8. a high-speed electron emitted from a nucleus
- 9. a force that opposes motion between two surfaces
- 10. material used to block or reduce radiation
- 11. the process by which an unstable nucleus becomes more stable
- 12. the tendency of an object to resist a change in motion
- 14. the splitting of a large atomic nucleus to release energy
- 15. the unit of force
- 16. the small, dense centre of an atom
- 18. natural radiation from sources like rocks and cosmic rays
- 21. the time taken for half of the radioactive nuclei to decay
- 22. forces that cause a change in motion
- 23. the ability of radiation to remove electrons from atoms
- 26. a type of counter used to detect radiation
- 28. energy or particles emitted from unstable nuclei
- 29. a single force that has the same effect as all the forces acting together
Down
- 1. speed in a given direction
- 2. an electromagnetic wave emitted from a nucleus
- 3. forces that are equal in size and opposite in direction
- 5. exposure to radiation without becoming radioactive
- 7. the amount of matter in an object
- 12. a pair of equal and opposite forces acting on two different objects
- 13. the product of mass and velocity
- 17. unwanted radioactive material on surfaces or inside objects
- 19. how far an object moves, regardless of direction
- 20. a particle made of 2 protons and 2 neutrons
- 24. atoms with the same number of protons but different numbers of neutrons
- 25. the constant speed reached when the weight is balanced by air resistance
- 27. the force that attracts objects towards the centre of the Earth