Name: __________________________________________ Period: ___ Date: _________

1. When you throw or catch a ball you exert a ______________________.
2. Define force.
3. What is net force.
4. What does the net force determine?
5. In which direction does an object accelerate?
6. What happens if the net force is zero?
7. Define balanced forces.
8. Define unbalanced forces.
9. Define friction.
10. In order for the car to reach a certain speed from rest the forces on the car must be __
11. Friction also effects objects that are _____________________.
12. What prevents a truck moving down hill when its breaks are set?
13. What does the frictional force depend on?
14. When are the frictional forces relatively great?
15. Why are the car designs changed?
16. What is air resistance?
17. What does the amount of air resistance on an object depend on?
18. Why does the apple fall down?
19. How does force of gravity differ from friction?
20. Define gravity.
21. What kind of objects has larger gravitational force?
22. On what other factor does the gravitational force depend on?
23. If the distance between two objects is doubled, how does it effect the gravitational force?
24. If the original distance between two objects is tripled, what happens to the gravitational force between them?
25. Gravitational forces are ______________ than the other type of forces.