1. Newton’s Laws of Motion

2. “A body will remain at rest or will continue to move with constant velocity unless external forces cause it to do otherwise” First Law of Motion This means that unless something else, such as friction or another force affects the body, it will continue to have the same velocity. Forces are measured in Newtons (N)

3. This object will continue to accelerate to the left as that is the only force applied to it. Examples 10N

4. 10N 10N This object will continue to have the same velocity. If it was already moving, it will stay at the same speed. If it wasn’t moving, it still won’t move.

5. What direction will this body move in? 5N 10N Practice

6. 5N 7N 16N 5N What is the Resultant Force?

7. F=ma Newton’s Second Law of Motion Force (N) =mass (kg) times acceleration (m/s 2 ) The force is proportional to the mass of the object it’s being applied to and that object’s acceleration

8. A body, A has mass 2kg and has a force of 50N applied to it, what is it’s acceleration? Solution F=ma therefore a=F/m F=50N m=2kg a=25ms 2 Examples

9. If a body of mass 5kg is accelerating at 2ms 2, what force has been applied to it? Solution F=ma m=5kg a=2ms 2 F=5x2=10

10. A body has a mass of 500 grams, if it is moving at i) 20ms 2 ii) 15ms 2 iii) 27ms 2 what force has been applied to it? Practice

11. What is the acceleration of this wheel? (It has a mass of 40kg) 10N 50N

12. “Action and Reaction are Equal and Opposite” Newton’s Third Law of Motion This means that if two things are in contact with each other, one of them pulls with the same magnitude of force that the other one is pushing.

13. You can test this out: push your hand against that of your neighbor, or push down against your desk. There is an equal reaction to you pushing down- otherwise the table would collapse onto the floor. 500N 500N

14. Friction is the most common application of Newton’s Third Law. If you push something very gently, it may not move. This is the opposite reaction, friction, stopping it moving. Some materials have more friction than others, such as glue. How many materials can you name that have strong friction? Examples