1. INERTIA

2. Inertia A property of a matter which resist change to the state of motion or rest. 3. Law of Inertia = Newtons 1st Law of MotionAn object at rest tends to stay at rest and a moving object tends to continue its uniform motion with the same speed and in the same direction unless being acted upon by an external force. 4. Law of InertiaAn object that is at rest will continue to be at rest unless an external force acts on it. 5. Law of InertiaAn object that is moving will continue to move in a straight line unless an external force acts on it. 6. Inertia in our daily lives 7. Examples of inertia in our daily livesWhen the cardboard is flicked, the coin falls into the glass. This is because the inertia of the coin maintains its state at rest and it falls into the glass due to gravity. 8. Examples of inertia in our daily lives The car was stop abruptly but the inertia of the man keeps him in the forward motion and throws him forward. 9. PhenomenaWhen the bus stops abruptly, the passengers lurch forward. 10. PhenomenaIf the bus accelerates suddenly, the passengers fall backward. 11. Phenomena When a car moves on a sharp bend, the passenger lurch outward. Why? 12. Phenomena Why does the dog shake itself after a bath? 13. Phenomena As you jump down from the merry go round, what must you do in order to avoid falling down. 14. Applications of inertia 15. Application A wet umbrella is rotated vigorously and then stops abruptly. Droplets of water on the umbrella are spun off because its inertia causes them to continue moving even when the umbrella has 16. Application What do you do to get the sauce out from the bottle? 17. Application The head of a hammer can be slotted into the hammer by knocking the bottom of the handle downwards on a hard surface. The hammer head will continue with its downward motion after the handle has come to a stop. This makes the upper part of the wooden handle slot deeper into the hammer head. 18. ApplicationWhat is the use of seat belt? 19. Experiment Inertia balance Take the time of 10 oscillations. Period = time for 1 oscillation The period of oscillation represents the inertia.What is the relationship between mass and Inertia? 20. A hacksaw can be used to replace inertia balance. Place plasticine at the end of the hacksaw as mass. Oscillate it 21. Aim: To investigate the relationship between mass and inertia. Inference: Hypothesis: Variables: mv: rv: cvMass, m (g) 20 40 60 80 100Time of 10 oscillations, t (s)Period, T = t/ (s) 10 22. Graph of T against m Period, T (s)?Mass, m (g) 23. What is the conclusion of the experiment? Mass increases, period of oscillation increases, therefore inertia increases. 24. Experiment The bucket filled with sand is more difficult to be pushed. Why? What is the relationship between mass and inertia?Mass increases, inertia increases. 25. Experiment When the string is pulled slowly, string P will snap. When the string is yanked suddenly, string Q will snap! Why?When the string is pulled slowly, string P has to bear the pulling force and the weight of the ball. When the string is yanked suddenly, the inertia of the ball prevents it from moving down therefore string Q snaps! 26. Phenomena Why is a sumo fighter so huge? 27. Phenomena Why is difficult for a train to stop?Why can Titanic stop in time to avoid crashing the iceberg? 28. Phenomena Why does a liquid product being carried in three separate compartment instead of one in a tanker truck? This is to reduce the inertia of the impact of the liquid if the truck stops suddenly.