Module 1 Motion

1. Module 1Motion

2. Speed, Velocity, & Acceleration • What is Speed? • Scalar Quantity (only have magnitude) • How fast something is moving • Distance traveled over time • No direction • Average speed is not instantaneous speed

3. Speed, Velocity, & Acceleration • Distance • Overall amount traveled

4. Speed, Velocity, & Acceleration • Units of speed are derived units of distance over time • Speed (meters/second) = distance (meters) /time (seconds)

5. Let’s Practice!!!! • In a skateboarding marathon, the winner covered 435 km in 36.75 h. What was the winner’s average speed? • Florence Griffith Joyner set a world record by running 200 m 21.34 s. What was her average speed? • An airplane is traveling at 400 mi/hr.  It touches down at an airport 2000 mi away.  How long was the plane airborne?

6. Speed, Velocity, & Acceleration • d/t graphs – X-axis = time – Y-axis = distance (position) • Speed on distance-time graphs – Think slope of line: check it out • Analyzing distance vs time graphs • ***Figure 7 in book***

7. Speed, Velocity, & Acceleration What was the object’s speed at 2 s? What was the object’s speed at 5 s? How would describe the motion of this car? What might you predict the next plot point to be?

8. Speed, Velocity, & Acceleration What was the object’s speed at 2 s? The object stopped during this time frame. When did this happen? Explain how you know. What happened between 9.8 s and 12 s? How do you know?

9. Speed, Velocity, & Acceleration How is this graph different? How would you describe the motion of this object? Can we still calculate speed?? How??

10. Speed, Velocity, & Acceleration

11. Speed, Velocity, & Acceleration • Frame of Reference • Motion is Relative to Frame of Reference • You observe how other objects move by comparing to that frame of reference

12. Speed, Velocity, & Acceleration • Velocity • Vector Quantity (magnitude and direction) • Speed and direction • Speed and Velocity are not the same

13. Speed, Velocity, & Acceleration • Velocity • Vector Quantity (magnitude and direction) • Speed and direction • Speed and Velocity are not the same

14. Let’s Practice!!!! • A cart starting from rest travels a distance of 3.6 meters northward in 1.8 seconds. What is the average velocity? • A car drives from Tallahassee to Orlando. The distance is 830 km and the drive takes 7.3 hrs. What is the velocity of the car?

15. Speed, Velocity, & Acceleration • Acceleration • Rate at which velocity changes • Speeding up (positive) • Slowing down (negative) • Changing direction

16. Speed, Velocity, & Acceleration • Calculating Acceleration

17. Let’s Practice !!!! • A roller coaster speeds up going down a hill from 0 m/s to 11 m/s at the bottom of the hill. If this occurs in 3 seconds, what is the acceleration of the roller coaster? • A cheetah is running at a velocity of 14 m/s and slows to tackle a wildebeast to 2 m/s. If the chase takes 4.2 seconds, what is the cheetah’s acceleration?

18. Speed, Velocity, & Acceleration • v/t graphs – X-axis = time – Y-axis = speed – Analyzing speed-time graphs – Think slope of line: – ***Figure 16 in book***

19. Speed, Velocity, & Acceleration Find the acceleration between 2-5 seconds. How would you describe this object’s motion? What would the next plot point would be? How do you know?

20. Speed, Velocity, & Acceleration Find the acceleration between 2-4 seconds. Find the acceleration between 7-9 seconds. What is happening between 4-7 seconds, How do you know??

21. Speed, Velocity, & Acceleration

22. The Laws of Motion • Force • A push or a pull • Measured in newtons

23. The Laws of Motion • Balanced and Unbalanced Forces

24. The Laws of Motion • Drawing and Interpreting Force Diagrams

25. The Laws of Motion • Net Force • Rules for Adding Forces • Add forces in the same direction. • Subtract forces in opposite directions • Forces not in the same directions\ or in opposite directions cannot be directly added together.

26. The Laws of Motion • Friction • Force that works against the motion of an object

27. The Laws of Motion • Newton’s 1st Law • An object at rest will stay at rest and an object in motion will stay in motion, unless an unbalanced force acts on it. • Break It Down: INERTIA – Things want to keep doing what they are doing • Inertia is directly related to mass.

28. The Laws of Motion • Newton’s 2nd Law • Acceleration of an object is directly affected by the net force acting on it, and inversely by the mass of the object

29. The Laws of Motion • Newton’s 2nd Law • Force (N) = mass (kg) x acceleration (m/s2)

30. Let’s Practice!!!! • With what force will a car hit a tree if the car has a mass of 3,000 kg and it is accelerating at a rate of 2 m/s2? • If a helicopter’s mass is 4,500 kg and the net force on it is 18,000 N upward, what is it’s acceleration?

31. The Laws of Motion • Newton’s 3rd Law • For every action (force applied) there is an equal and opposite reaction (resulting force)

32. The Laws of Motion • Momentum • Mass of an object times its velocity • A vector quantity (magnitude and direction) • Momentum = mass x velocity

33. The Laws of Motion • Conservation of Momentum • Momentum remains constant for objects interacting with one another in a system

34. Let’s Practice!!!!

35. Let’s Practice!!!!

36. Let’s Practice!!!!

37. The Laws of Motion • Angular Momentum • Deals with rotational motion • Is a product of mass and velocity • Depends on the distribution of mass • Angular mass (moment of inertia)

38. Forces in Action • 4 basic Forces • Gravititational • Electromagnetism • Strong nuclear force • Weak nuclear force

39. Forces in Action • Gravitational • Force of attraction between two objects • Depends on mass and distance • Weakest of the four forces

40. Forces in Action • Gravity and Weight • Measures the force of gravity on mass • Weight and Mass are different things

41. Forces in Action • Falling for Gravity • Force of air friction between falling object and air particles • All objects regardless of mass, experience the same acceleration when in free fall

42. Forces in Action • Electromagnetic Forces • Forces occur when electric field interacts with electrically charged particles • Opposite charges attract, like charges repel

43. Forces in Action • Strong Nuclear Forces • Work at the atomic level • Strong Forces • Force that holds the nucleus of atom together • Strongest of the 4 forces, short range

44. Forces in Action • Weak Nuclear Forces • Work at the atomic level • Weak Forces • Force responsible for particle decay (radioactivity)

45. Forces in Action

46. Energy • Energy • Ability to change or move matter • Exists in many forms • Potential • Nuclear • Elastic • Chemical • gravitational • Kinetic • Electrical • Radiant • Thermal • Mechanical

47. Energy

48. Energy • Energy Conversions • Law of Conservation of Energy • Energy cannot be created or destroyed, just converted from on form to another

49. Energy • Kinetic Energy – energy of motion – depends on mass and speed • Kinetic Energy = ½ mass x speed (KE = ½ m v2) KE (J) = ½ m (kg) X v (m/s)2

50. Energy • What is the kinetic energy of a 136.4 kg elephant moving at 34 m/s? •What is the kinetic energy of a 22.7 kg boy on his 45.5 kg bike rolling down a hill 25 meters high at 7.21 m/s? • Determine the kinetic energy of a 1000-kg roller coaster car that is moving with a speed of 20.0 m/s.