Presentation is loading. Please wait.

Presentation is loading. Please wait.

Note: Slides are animations, so make sure to ’play’ them Homework Study examples at home for tomorrow’s special do now activity that has.

Published byJemima Tate Modified over 6 years ago

Similar presentations

Presentation on theme: "Note: Slides are animations, so make sure to ’play’ them Homework Study examples at home for tomorrow’s special do now activity that has."— Presentation transcript:

1

2

3

4

5

6

7

8 Note: Slides are animations, so make sure to ’play’ them
Homework Study examples at home for tomorrow’s special do now activity that has the potential to affect your grade Note: Slides are animations, so make sure to ’play’ them

9 Law of Conservation of Energy
The total amount of energy in a closed system must remain constant – energy is never created or destroyed. Mechanical Energy = PE (both spring/gravitational) + KE Heat or Work done by friction = Q (Internal Energy)

10 Conservation of Energy

11 Example #1 – Cliff Diver A 500 newton cliff diver climbs to a height of 50 meters above the water. What is his total energy at the top of his climb? ET = PE + KE + Q ET = mgh + ½ mv2 + 0 ET = (500 N)(50 m) ET = J

12 Example #1 – Cliff Diver A 500 newton cliff diver climbs to a height of 50 meters above the water. What is his potential energy at the point where he is 40 meters above the water’s surface? ΔPE = mgΔh ΔPE = (500 N)(40 m) ΔPE = J

13 Example #1 – Cliff Diver A 500 newton cliff diver climbs to a height of 50 meters above the water. What is his kinetic energy at that point? ET = PE + KE + Q 25000 J = J + KE + 0 KE = 5000 J

14 PEtop = 25,000 J (relative to the water!) KEtop = 0 J
50 m PEmiddle = 12,500 J KEmiddle = 12,500 J 25 m 0 m PEbottom = 0 J KEbottom = 25,000 J

15 Example #2 – Carts and Hills
ETOT = PE + KE + Q ETOT = J + 50 J + 0 ETOT = J KE = ½ mv2 KE = ½ (4.0 kg)(5 m/s)2 KE = 50 J KE = ½ mv2 J = ½ (4.0 kg)v2 v = 8.0 m/s Example #2 – Carts and Hills A 4.0 kilogram cart operating on a frictionless track has a speed of 5.0 meters per second while at the top of a 2.0 meter high hill. What is the cart’s total energy at the top of the hill? ET = PE + KE + Q ET = mgh + ½ mv2 + 0 (frictionless) ET = (4.0 kg)(9.81 m/s2)(2.0 m) + ½ (4.0 kg)(5.0 m/s)2 ET = J

16 Example #2 – Carts and Hills
A 4.0 kilogram cart operating on a frictionless track has a speed of 5.0 meters per second while at the top of a 2.0 meter high hill. What is the cart’s speed at the bottom of the hill? ET = PE + KE + Q J = 0 + ½ mv2 + 0 J = ½ (4.0 kg)v2 v = 8.0 m/s

17 Example #3 – Spring Toy A spring toy with a mass of .002 kg has a spring with a spring constant of 120 newtons per meter. The toy is compressed .04 m. How much energy can be stored in the toy’s spring? PES = ½ kx2 PES = ½ (120 N/m)(0.04 m)2 PES = J

18 Example #3 – Spring Toy A spring toy with a mass of 2.0 grams has a spring with a spring constant of 120 newtons per meter. The toy is compressed 4.0 centimeters. What maximum height will the spring toy reach if it is released? ΔPE = mgΔh 0.096 J = (0.002 kg)(9.81 m/s2) h h = 4.9 m

19 Label points where potential and kinetic energies are maximum/minimum.
Example #4 – Pendulum Label points where potential and kinetic energies are maximum/minimum. PE max KE = 0 KE = 0 PE max KE max PE min

20 Walter Lewin MIT Demo

Download ppt "Note: Slides are animations, so make sure to ’play’ them Homework Study examples at home for tomorrow’s special do now activity that has."

Similar presentations

Energy Problems Review for Potential energy, Kinetic energy, Total Energy work, power.

Energy Problems Review for Potential energy, Kinetic energy, Total Energy work, power.
ENERGY TRANSFORMATION. ● The Law of Conservation of Energy states that energy cannot be created nor destroyed. ● Energy can be transformed from one form.

ENERGY TRANSFORMATION. ● The Law of Conservation of Energy states that energy cannot be created nor destroyed. ● Energy can be transformed from one form.
Conservation of Energy Energy is Conserved!. The total energy (in all forms) in a “closed” system remains constant The total energy (in all forms) in.

Conservation of Energy Energy is Conserved!. The total energy (in all forms) in a “closed” system remains constant The total energy (in all forms) in.
Emech at 1 + W = Emech at 2 mgh1 = mgh2

Emech at 1 + W = Emech at 2 mgh1 = mgh2
Energy.

Energy.
Principles of Physics - Foederer. Energy is stored in a spring when work is done to compress or elongate it Compression or elongation= change in length.

Principles of Physics - Foederer. Energy is stored in a spring when work is done to compress or elongate it Compression or elongation= change in length.
Potential and Kinetic Energy Problems

Potential and Kinetic Energy Problems
CONSERVATION OF MECHANICAL ENERGY

CONSERVATION OF MECHANICAL ENERGY
It takes work to lift a mass against the pull (force) of gravity The force of gravity is m·g, where m is the mass, and g is the gravitational acceleration.

It takes work to lift a mass against the pull (force) of gravity The force of gravity is m·g, where m is the mass, and g is the gravitational acceleration.
Energy By. Jonathan Lee and Harry Chun. What is “energy”? Energy is the ability to do work Potential Energy (PE) is the “possible” ability to do work.

Energy By. Jonathan Lee and Harry Chun. What is “energy”? Energy is the ability to do work Potential Energy (PE) is the “possible” ability to do work.
Physics 121 6. Work and Energy 6.1 Work 6.3 Kinetic Energy 6.4 Potential Energy 6.5 Conservative and Non-conservative forces 6.6 Mechanical Energy /

Physics Work and Energy 6.1 Work 6.3 Kinetic Energy 6.4 Potential Energy 6.5 Conservative and Non-conservative forces 6.6 Mechanical Energy /
Chapter 5 Work, Energy, Power Work The work done by force is defined as the product of that force times the parallel distance over which it acts. The.

Chapter 5 Work, Energy, Power Work The work done by force is defined as the product of that force times the parallel distance over which it acts. The.
Energy and Conservation Physics Chapter 5-2 (p172-178) Chapter 5-3 (p179-183)

Energy and Conservation Physics Chapter 5-2 (p ) Chapter 5-3 (p )
ENERGY The measure of the ability to do work Conservation of energy -energy can change forms but can not be destroyed -the total amount of energy in the.

ENERGY The measure of the ability to do work Conservation of energy -energy can change forms but can not be destroyed -the total amount of energy in the.
How much work does a 154 lb. student do when climbing a flight of stairs that are 6 meters in height and 30 meters in length? If the stairs are climbed.

How much work does a 154 lb. student do when climbing a flight of stairs that are 6 meters in height and 30 meters in length? If the stairs are climbed.
Physics 3.3. Work WWWWork is defined as Force in the direction of motion x the distance moved. WWWWork is also defined as the change in total.

Physics 3.3. Work WWWWork is defined as Force in the direction of motion x the distance moved. WWWWork is also defined as the change in total.
Energy and Power.

Energy and Power.
Types of Energy and the law of conservation of energy p. 236-241.

Types of Energy and the law of conservation of energy p
Energy Chapter 7.

Energy Chapter 7.
Sect. 6-5: Conservative Forces. Conservative Force  The work done by that force depends only on initial & final conditions & not on path taken between.

Sect. 6-5: Conservative Forces. Conservative Force  The work done by that force depends only on initial & final conditions & not on path taken between.

Similar presentations

Ads by Google