2. Motion

3. Motion Motion occurs when the distance between two or more objects changes. This is not as simple as it sounds. Motion is all relative to a reference point. You may think that by sitting completely still in your chair means you are motionless, and you are if you use the floor as a reference point. If, however, you use the sun as a reference point, you would be moving at a speed of over 65,000 miles. When determining motion, it is important to determine a reference for your motion.

4. Speed Speed of motion is calculated by dividing the distance traveled by the time taken to travel that distance.

5. 2,500 miles If it takes the plane 6.0 hours to travel 2,500 miles from NY to LA, what was the average speed was it traveling? speed = distance time speed = 2,500 miles 6.0 hours speed = 416.6 miles/hour

6. Acceleration Acceleration occurs when an object’s speed and/or direction changes. If the object slows down, it is negative acceleration or deceleration.

7. Initial Speed = 0.0 m/s Final Speed = 4.0 m/s Time = 2.0 seconds Accel = S f – S i Time Accel = 4.0 m/s – 0.0 m/s 2.0 s Accel = 4.0 m/s 2.0 s Accel = 2.0 m/s 2 Initial Speed = 0.0 m/s Final Speed = 4.0 m/s Time = 2.0 seconds

8. How fast would I be going if I continued at this rate of acceleration for another second? This means that as I was going down the rollercoaster, my speed was increasing 2.0 m/s every second. First I was going 0.0 m/s, then after a second, I was going 2.0 m/s. After another second, I was going 4.0 m/s.

9. On Earth and other planets (or anything that has mass) a gravitational force pulls on objects towards its surface and causes it to accelerate. On Earth, the acceleration due to gravity for all objects regardless of mass is 9.8 m/s 2 (Neglect air resistance). This means that as things are in free fall (on gravity is acting on it), every second that goes by, the object’s speed will increase by 9.8 m/s.

10. t = 0.0 sec. s = 0.0 m/s t = 1.0 sec. s = 9.8 m/s t = 2.0 sec. s = 19.6 m/s t = 3.0 sec. s = 28.4 m/s Acceleration due to gravity on Earth is 9.8 m/s 2 ! If the ball has a mass of 10.0 kg, what is its weight in Newtons?

11. A force is a push or a pull. When there are balanced (equal) forces acting oppositely on an object, no motion occurs. 50 N No Motion

12. When there are unbalanced (unequal) forces acting oppositely on an object, motion results in the direction of the greater force. 100 N 50 N

13. Friction is a force that always opposes motion. Because of this, friction causes things to slow down. There are different types of friction such as rolling, sliding, and static friction. Air resistance is also a type of friction known as fluid friction.

16. Less Surface Contact

17. Motion Friction

18. Which will hit the ground first? Air Resistance (friction)

19. Which will hit the ground first? Vacuum (no air) In a vacuum, there’s no air resistance.

20. On the Moon there is no air resistance !

21. Apollo 15 Commander Dave Scott

22. W = 400 N W = 300 N

23. W = 400 N W = 300 N A.R. = 400 N A.R. = 300 N

24. Forces Kick Butt! Oh my Gosh, you killed Kenny! You Balanced Forces!

25. Projectile Motion A projectile is a moving object that is not being propelled. (Gravity may be acting upon it) Examples: a baseball after it has been thrown, a rocket after the engines have been turned off, an arrow after it has left the bow

26. In projectile motion, horizontal motion and vertical motion are independent of one another. In other words, if Scrat were to jump straight out for the acorn, his horizontal velocity would remain the same as each second went by. But… His vertical speed would change as gravity accelerated him downward.

28. The Acorn is About to Fall

29. Get Ready for the Jump

31. The Jump Took 3 Seconds. Look closely at the horizontal & vertical distances as each second passes. 0 1 2 3

32. I Love Projectile Motion

33. 5 meters A Crabby- Patty !?! DON’T DROP IT!