1. Newton’s Laws

2. 2 Vectors and scalars Vectors A quantity that has 2 dimensions, MAGNITUDE and DIRECTION Scalars A quantity that has a single dimension MAGNITUDE

3. 3 Vectors and scalars TermDefinitionVector or Scalar displacement temperature Speed Velocity Distance Acceleration Forces Weight deceleration mass

4. 4 Forces F=MA Forces cause ; A force is a “A force is that which alters or to alter a body’s or of in a line.” If a body changes or, a has been applied force movement push or a pull tends state of rest uniform motionstraight directionvelocity

5. 5 Forces affecting motion External Reaction forces Gravity Air resistance/friction Internal Muscular contractions Vertical Weight – mass x acceleration Gravity Air resistance/friction Reaction force Horizontal Friction Air resistance

6. Impulse Impulse = force x time The length of time a force is applied to an object or body and therefore change in momentum Sporting examples?

7. Reaction force Reaction force always occur when 2 bodies are in contact Act at 90 degrees to contacted surface

8. 8 Forces affecting motion Unbalanced Where a force acting in 1 direction is larger than that acting in the opposite direction Object or body will start to move or accelerate/decelerate in the direction of the bigger force Balanced 2 or more forces are of equal size but in opposite direction All the forces cancel themselves out so zero net force Object or body will remain stationary or remain constant in its velocity

9. 9 Ground Reaction Force Action force of muscle contraction Equal and opposite Ground Reaction Force

10. 10 Forces applied - runner ‘action force’ applied to ground Reaction force from between ground and foot Air resistance Muscular ground Gravity Friction to forward motion

11. 11 Forces acting on a sprinter Action force of muscular contraction Friction Gravity Air resistance Equal and opposite Ground Reaction Force

12. 12 Forces applied – high jumper ‘action force’ applied to ground Reaction force from - large vertical component between ground and foot Air resistance Muscular ground Gravity Friction to forward motion

13. 13 Forces applied – kicking forces applied to ball Reaction force from between ball and foot Air resistance Muscular ball Gravity Friction to forward motion

14. 14 Newton’s Laws 1st Law – A body will remain in its / until affected by a A body has a to change its Law of inertia state of motion reluctance restforce state of motion

15. 15 Applying Newton’s 1 st Law Sprinter remains in on blocks until a causes him to change his Ball keeps moving until a causes it to change its force set position force state of motion

16. 16 Momentum In sporting situations, remains constant; therefore inertia All objects in motion have mass and Product = Momentum = mass x velocity mass stays the same velocity momentum

17. 17 Newton’s Laws 2nd Law – The rate of change of is to the force causing the change, and the change takes place in the in which the force was applied In sport, remains constant and therefore momentum equates to Law of acceleration momentum directly proportional direction mass acceleration

18. 18 Applying Newton’s 2 nd Law The (size) and of force applied by the sprinter to the blocks determines the and of received – because mass remains constant Acceleration is to applied magnitudedirection magnitudedirection acceleration proportionalforce F = ma

19. 19 Newton’s Laws 3rd Law –Law of Reaction To every force there is an and reaction force equal opposite

20. 20 Applying Newton’s 3 rd Law The sprinter applies a to the ground. This results in a force causing movement The sprinter cannot move the Reaction force from ground = muscular force reaction earth/blocks Ground Reaction Force

21. Extended work Tomorrow’s lesson, you will be in groups of 4. With use of video camera and practical performer you will apply Newton’s 3 Laws of Motion to your choice of a sporting situation

22. 22 Typical question Use Newton’s Three Laws of Motion to explain how a tennis player moves towards the ball in preparation to play a stroke. (5 marks)

23. 23 Answer First Law – reluctance to change state of motion/constant motion/ uniform motion/velocity; Force required to change state of motion/overcome inertia of player; Muscle contractions;(Sub max 2 marks) Second Law – magnitude/size of force governs change in momentum; Mass remains constant; Force governs magnitude of acceleration given to player; And direction;(Sub max 2 marks) Third Law – equal and opposite reaction force; Force applied to ground/ moves performer; Ground Reaction Force.(Sub max 2 marks) Max of 5 marks Do not credit Force = Mass x Acceleration Only credit responses that relate to the player not the ball.