Force and Motion: Part 5

1. Newton’s Laws of Motion Force and Motion: Part 5

2. Newton’s Laws of Motion Sir Isaac Newton 1642 - 1727

3. Laws of motion • An object at rest stays at rest until something moves it. An object in motion will remain in motion until something stops it. • An object with less mass will accelerate more than an object with greater mass when you apply the same force. The greater the force applied to an object, the greater the acceleration. • For every action there is an equal opposite reaction.

4. Inertia The tendency of an object to resist any change in motion is known as inertia. Law 1 An object at rest stays at rest until something moves it. An object in motion will remain in motion until something stops it.

5. Inertia

6. Inertia And an object in motion will remain in motion until something stops it.

7. Acceleration Law 2 An object with less mass will accelerate more than an object with greater mass when you apply the same force. The greater the force applied to an object, the greater the acceleration.

8. Law 3 For every action there is an equal opposite reaction.

9. Question Why don’t I fall out when a roller coaster goes upside down?

10. Answer  Gravity is counteracted by the force of acceleration, which is the force that pushes you forward.

11. When you go around a turn, you feel pushed against the outside of the car. This force is “centripetal force” and helps keep you in your seat. • In the loop-the-loop upside down design, it’s inertia that keeps you in your seat. Inertia is the force that presses your body to the outside of the loop as the train spins around. Although gravity is pulling you toward the earth, at the very top the acceleration force is stronger than gravity and is pulling upwards, thus counteracting gravity. The loop however must be elliptical, rather than a perfect circle, otherwise the centripetal (g) force would be too strong for safety and comfort.

12. Design your own Roller Coaster • http://www.learner.org/interactives/parkphysics/coaster/