1. Forces, Motion, and Machines

2. A push or pull that is applied to an object

3. Force

4. The force that pulls objects toward the center of the Earth

5. gravity

6. Going from one place to another

7. Motion
a bus, train, and airplane are in motion when they move from one place to another

8. A force that stops motion and happens between two surfaces that touch

9. It is easier to walk on a dry surface than it is on ice
Friction
It is easier to walk on a dry surface than it is on ice

10. A lifting or raising force

11. A kite depends on the wind to act as its lift.

12. Resistance by friction from air or water moving over a surface

13. drag
Boats and planes are narrow. As they move, friction holds them back from moving faster.

14. A reaction force that pushes objects forward

15. Airplanes, rockets, motor boats use thrust to move

16. A change in speed, direction, or both

17. acceleration

18. The speed and direction of moving objects

19. velocity