mechanics

3. The quantity of motion of a moving body, measured as a product of its mass and velocity.
4. Two forces acting in opposite directions on an object, and equal in size.
5. An external force is required to make an object __________
7. A force that slows down and object
8. Newton's third law is action
11. It is created by a planes engines to move it forward
14. The total energy of the system does not change and colliding objects bounce after collision
15. It is the same where ever you go
17. It is something that measures weight which is sometimes called a spring-balance
18. Overall force acting on an object.
19. An encounter between two objects resulting in exchange of impulse and momentum
20. The total kinetic energy of the system changes

1. When no momentum is gained or lost the momentum is _______
2. This is the downward force acting on a mass and is caused by gravity
6. force that points towards center
9. The rate at which an object covers distance.
10. Objects that stick together after collision
12. If we want to change the _________ of an object, an external force is required
13. This is when you are moving down at a steady speed
16. The speed of an object plus its direction.