2. Newton’s Laws of Motion

3. Question #1 – just think about it, don’t write it down. A bus driver slams on his brakes. All of the backpacks on the floor slide forward. Why does this happen? A bus driver slams on his brakes. All of the backpacks on the floor slide forward. Why does this happen?

5. Newton’s First Law: The Law of Inertia An object in motion will stay in motion and an object at rest will stay at rest…until an outside force acts on it. Definition of Inertia: An object’s resistance to a change in motion.

6. Mass is the measure of Inertia

7. Weight is a Force The force with which an object is attracted toward a celestial body (earth, moon, sun, etc…) by gravity.

8. Difference Between Mass and Weight Mass the measure of inertia. Mass the measure of inertia. The mass of an object does not change based on it’s location The mass of an object does not change based on it’s location 10kg on the moon is 10kg on Earth. 10kg on the moon is 10kg on Earth. Weight is a force. A 75 kg man weighs around 160 lbs. on Earth. He is still 75 kg on the moon, but he weighs 27 lbs. on the moon because the moon is smaller and has less of a gravitational pull.

9. Whiplash

10. Inertia in Photography A screwdriver was dropped on a water balloon and for a moment after the balloon broke away the water maintained the same shape. Which has more mass? The balloon or the water? Which resisted a change in motion more? The balloon or the water?

11. What is a Force?

12. Definition of Force A force is a push or pull that causes an object to accelerate.

13. Newton’s Second Law Force = Mass x Acceleration F = ma

14. Units of Force Forces are measured in units called “Newtons” (N) A 20 N Force is required to accelerate a 10kg ball by 2m/s 2 F = ma F = 10(2) = 20 N

15. Use “g” when dealing with gravity F = mg This is the equation to find the force of gravity pulling on an object g = 10 m/s 2

16. Friction Friction is a force that occurs when two objects come in contact with one another. It is like a “sticky” force Friction causes moving objects to slow down, and therefore accelerate, so it is a force Even very smooth objects are rough at a microscopic level. This roughness is what causes friction.

17. Newton’s Third (and final) Law of Motion: Action-Reaction When one object exerts a force on a second object, the second object exerts an equal force in the opposite direction back onto the first object When one object exerts a force on a second object, the second object exerts an equal force in the opposite direction back onto the first object Sometimes stated “every action has an equal and opposite reaction.” Sometimes stated “every action has an equal and opposite reaction.”

19. F 1 = -F 2 F 1 = -F 2 If the mass is big, the acceleration is small. If the mass is small than it has a greater acceleration. mA =Ma

20. Newton’s 3 rd Law is Why Guns Have Recoil Recoil is the force felt by a shooter from the gun as it is fired. Recoil is the force felt by a shooter from the gun as it is fired.