1. Effects of Forces
Change shape

2. Effects of Forces
Change shape

3. Change of Shape

4. Force is directly proportional to extension

5. Force is directly proportional to extension
When force doubles, the extension doubles
F α x F
= constant x
Hooke’s Law

6. Force is directly proportional to extension= x1 x2 m1 m2 = x1 x2

7. What if we put more weights than we did?
Elastic Limit

8. Effects of Forces Change the state of motion Move from rest Speed up
Slow down
Stop
Change its direction

9. Balanced forces

10. Balanced Forces
The book stays still!

11. The airplane moves forwards at constant speed!
Balanced Forces
The airplane moves forwards at constant speed!

12. The car moves at constant speed!
Balanced Forces
Thrust
Drag
Friction
The car moves at constant speed!

13. Unbalanced Forces
The car moves from rest.
The car speeds up.

14. Unbalanced Forces
The car slows down to stop.
The car slows down.