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M.I.T. C.P. Physics ENERGY.

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Presentation on theme: "M.I.T. C.P. Physics ENERGY."— Presentation transcript:

1 M.I.T. C.P. Physics ENERGY

2 Energy is the ability to do work. Work = Force X Distance X cosΘ
What is Energy? Energy is the ability to do work. Work = Force X Distance X cosΘ

3 Types of Energy Kinetic Energy Energy of Motion KE = ½ mv^2

4 Lab: Validating the KE Formula
Interactive

5 Lab: Validating the KE Formula
Data Chart Trial # KE (J) Mass (kg) Time (s) Distance (m) 1 2 3 4 5

6 Lab: Validating the KE Formula
Calculation Chart Trial # Velocity (m/s) 1 2 3 4 5

7 Lab: Validating the KE Formula
Analysis Chart Trial # KE (J) 1/2mv^2 1 2 3 4 5

8 Theoretical Physics

9 Calculate the kinetic energy of a 750-kg car moving at 13.9 m/s.
Sample Problem 1 Calculate the kinetic energy of a 750-kg car moving at 13.9 m/s. Step 1 KE = ½ mv^2 Step 2 KE = ½ (750)(13.9)^2 Step 3 KE = 7.2 x 10^4J

10 What is the kinetic energy of the car if the speed is doubled?
Sample Problem 2 What is the kinetic energy of the car if the speed is doubled? Step 1 KE = ½ mv^2 Step 2 KE = ½ (750)(27.8)^2 Step 3 KE = 3.0 x 10^5J

11 Sample Problem 3 How much work must be done to double the speed of the car? Work = Force X Distance X cosΘ The metric unit for KE = joules. The metric unit for work = joules.

12 Work Energy Theorem Work must be done to speed up the car or slow down the car. As the speed of the car changes, so does its KE. Work = ΔKE

13 How much work must be done to double the speed of the car?
Sample Problem 3 How much work must be done to double the speed of the car? Step 1 W = ΔKE Step 2 W = (3.0 x 10^5)-(7.2 x 10^4) Step 3 W = 2.2 x 10^5J

14 Stored Energy or Energy of Position
Types of Energy Potential Energy Stored Energy or Energy of Position

15 Types of Potential Energy
Chemical Potential Energy

16 Types of Potential Energy
Electrical Potential Energy

17 Types of Potential Energy
Elastic Potential Energy Elastic Potential Energy = ½ kx^2

18 Types of Potential Energy
Gravitational Potential Energy Gravitational Potential Energy = mgh

19 Sample Problem A 150-kg Humpty Dumpty sat on a 2.5 meter wall. What is Humpty Dumpty’s potential energy before his great fall? Step 1 PE = mgh Step 2 PE = (150)(9.8)(2.5) Step 3 PE = 3700J

20 Law of Conservation of Energy
Energy can not be created nor destroyed, only changed. The total energy of a system remains constant.

21 Energy Conversion Total Mechanical Energy = PE + KE
As the boy swings down, his PE decreases while his KE increases.

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23 Energy Conversion Total Mechanical Energy = PE + KE
As the boy swings down, his PE decreases while his KE increases. As the boy swings up, his PE increases while his KE decreases.

24

25 Interactive

26 Sample Problem A D B E C F

27 Lab: Conservation of Energy
Interactive

28 Lab: Conservation of Energy
Data Chart Height (m) PE (J) KE TME 6 5 4 3 2 1

29 Sample Problem A 7.26-kg bowling ball is dropped from a height of 2.5 meters into a toilet. What speed will the bowling ball hit the water? Step 1 PE = mgh Step 2 PE = (7.26)(9.8)(2.5) Step 3 PE = 180 J

30 Sample Problem A 7.26-kg bowling ball is dropped from a height of 2.5 meters into a toilet. What speed will the bowling ball hit the water? Step 4 PE = KE = ½ mv2 Step 5 180J = ½ (7.26)v^2 Step 6 V = 7.0m/s

31 Sample Problem Check A 7.26-kg bowling ball is dropped from a height of 2.5 meters into a toilet. What speed will the bowling ball hit the water? Step 1 D = ½ gt^2 Step 2 2.5 = ½ (9.8)t^2 Step 3 t = .71s

32 Sample Problem Check A 7.26-kg bowling ball is dropped from a height of 2.5 meters into a toilet. What speed will the bowling ball hit the water? Step 4 v = gt Step 5 v = (9.8)(.71) Step 6 v = 7.0m/s

33 Introduction to Engineering

34 Conservation of Energy
Roller Coaster Physics

35 Lab: Roller Coaster Challenge
Interactive

36 Lab: Roller Coaster Challenge
Objectives The coaster must finish the whole course! Determine the fastest and slowest time possible to complete the course.

37 Lab: Roller Coaster Challenge
Data Chart Fastest Time Slowest Time

38 Roller Coaster Design Kingda Ka 200 km/h 3.5 seconds 20,800 hp
$25,000,000

39 Roller Coaster Physics

40

41 G Force

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43 Roller Coaster Physics

44 Roller Coaster Physics

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49 Roller Coaster Physics

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51 Lab: More Thrills with Fewer Ills!

52 Lab: More Thrills with Fewer Ills!

53 Lab: More Thrills with Fewer Ills!
Calculation Chart Values Standard Loop Chothoid Loop PE1 v1 KE1 TME1 TME2 v2 Ac G Force1 TME3 v3 29.73 m/s G Force2

54 Introduction to Engineering

55 Elasticity

56 Elasticity A material’s ability to return to its original shape after being deformed.

57

58

59

60 Vocabulary

61 Change in shape of an object.
Deformation Change in shape of an object.

62 Strain

63 Applied Force / Original Area
Stress Applied Force / Original Area

64 Types of Stress Tension-Compression

65 Types of Stress Shear

66 Types of Stress Hydrostatic

67 Stress Strain Curve

68 Elastic Limit

69 Youngs’ Modulus

70 Hooke’s Law F = kx k = Spring Constant

71 Lab: Special “k”

72 Not This Special “K”

73 Lab: Special “k” Data Chart Spring # Length 1 (m) Force (N) Length 2 1
3 4 5 6

74 Lab: Special “k” Conversion Formulas Centimeters to Meters cm/ 100 = m
Grams to Newtons g/1000 x 9.81 = N

75 Lab: Special “k” Calculation Chart Spring # Force (N) ΔX (m) K (N/m) 1
2 3 4 5 6

76 Sample Problem A 0.50 newton weight is dropped onto a spring causing it to compress .46 m. Calculate k. Step 1 F = kx Step 2 0.50 = k (.46) Step 3 k = 1.1 N/m

77 Sample Problem 2 A 4kg block slides across a frictionless table with a velocity of 5m/s into a spring with a stiffness of 2500N/m. How far does the spring compress? Step 1 ½ mv^2 = ½ kx^2 Step 2 50J = ½ (2500) x^2 Step 3 X = .2 meters

78 Stress Strain Curve

79 Ultimate Stress

80

81 Lab: Ultimate Stress


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