PE and KE Energy!

Potential Energy (PE) What is potential? Examples of using the term “Potential” You have the potential to do well on the Ch. 3 Test The Cubs had the potential to make it to the World Series Definition: anything that may be possible to DO something Potential energy is STORED ENERGY due to its position, shape, or state This is called potential energy It has the potential to cause a change

Potential Energy Stored Gravitationally Question: A bowling ball sits on a table. If it rolled off, how much damage could it do to your foot? What things could change about the ball so that it might cause more or less damage on my foot? Factors that effect PE -height -gravity -mass PE = m∙g∙h

PE = mgh Complete the table below by finding the potential energy. MASS GRAVITY HEIGHT P.E. 5 kg _____ 1 meter ____J 5 kg _____ 2 meters ____J 5 kg _____ 10 meters ____J 5 kg _____ 20 meters ____J As height increases? Is PE increasing? Are they proportional? Directly proportional? 9.8 m/s2

PE = mgh What is the PE of an egg with a mass of 0.5 kg that is held at a height of 3 m.? G U E S  

PE = mgh What is the mass of a car that is 6 m off the ground and has a PE of 72,000 J ? G U E S  

Kinetic Energy Motion KE = ½ m ∙ v2 The Energy of KE depends on: Velocity Mass KE = ½ m ∙ v2

Complete the table below by finding kinetic energy: MASS VELOCITY KINETIC ENERGY 1 kg 2 m/s _______ J 2 kg 2 m/s _______J 4 kg 2 m/s _______J 8 kg 2 m/s _______J As mass increases, is KE increasing? Are they proportional? Directly proportional?

Complete the table to find the kinetic energy: MASS VELOCITY KINETIC ENERGY 4 kg 1 m/s ______J 4 kg 2 m/s ______J 4 kg 4 m/s ______J 4 kg 8 m/s ______J Is velocity increasing? Is KE increasing? Are they proportional? Directly proper ional?

What is the KE of a cart that has a mass of 48 kg and a velocity of 3 m/s.? U E S  

What is the mass of a bowling ball moving at 10 m/s that has a KE of 800J. ? U E S  

60 mph? ____________________ Which has a greater kinetic energy – a truck traveling at 30 mph or a Beetle car traveling at 60 mph? ____________________ 1x’s mass x 60 mph = ________J of KE 2x’s mass x 30 mph = _________ J of KE

Law of Conservation of Energy Total Energy What did you notice about the TOTAL energy bar graph? Total amount of energy remains constant 2 Parts: Energy Transfers Cannot create or destroy Energy Total Energy = KE + PE

Forms of energy Ep Ek Eel Ec Et ET Potential energy Kinetic energy Elastic energy Chemical energy thermal energy Total energy

Energy changes from E?... to E?…

https://phet.colorado.edu/en/simulation/energy-skate-park

TOTAL amount of energy remains CONSTANT

Law of Conservation of Energy Energy cannot be created or destroyed: It can be transformed (changed) from one form to another, But the TOTAL amount of energy Always stays the SAME.

Law of Conservation of Energy

Determine the amount of PE at each position

A 0.5 kg ball rolling down the frictionless ramp. KE PE Eel ET KE PE Eel ET KE PE Eel ET PE = _____ KE = _____ Total E = _____

LOL Diagrams KE PE Et ET KE PE Et ET KE PE Et ET X X X

Bell work: 11/30 A B C D KE PE Et ET KE PE Et ET KE PE Et ET 4 PE = _____ PE = _____ PE = _____ PE+KE = _____ KE = _____ KE = _____ KE = _____ Et = _____ Total E = _____ Total E = _____ Total E = _____ Total E = _____ 2 4 4 4

Ramp Lab Part 1: height Stopping distance height

Energy Ramp Lab: Part 1 If we elevate the position of a ball, we give it PE. Raise it twice as high and it has twice the energy. Another way of saying it has twice the energy is to say it has twice the ability to cause a change in another object. In sliding down a ramp, it creates thermal energy due to friction. The question is raised: Will it skid twice as far if it has twice the energy before it comes to a stop? Q: What will be the stopping DISTANCE of a marble if we were to release it from a greater HEIGHT (giving it more PE)?

Energy Ramp Lab 0.40 m Height 1.50 m 1.20 m .90 m .60 m .30 m 0 m PE = _____ PE = _____ PE = _____ PE = _____ PE = _____ PE = _____ KE = _____ KE = _____ KE = _____ KE = _____ KE = _____ KE = _____

Energy Ramp Lab 0.40 m Height 1.50 m 1.20 m .90 m .60 m .30 m 0 m PE = _____ PE = _____ PE = _____ PE = _____ PE = _____ PE = _____ KE = _____ KE = _____ KE = _____ KE = _____ KE = _____ KE = _____

Graph of Data Table A Distance (m) Distance vs. Height Height (m)

Question 1 Based on your data, state the relationship between height and distance: Distance vs. Height Average Distance (m) 0 .5 1.0 1.5 2.0 2.5 0 .10 .20 .30 .40 Height (m)

Energy Ramp Lab Results What is the relationship between HEIGHT and stopping distance? If the TOTAL energy of marble is 0.025 J, what is the potential energy half-way down the ramp? What is the KE at the bottom of the ramp?

Part 2 Purpose Q: What will happen to the stopping DISTANCE of the marble if we were to release it from a greater INCLINE (steeper slope)? 20 cm Angle ° Angle ° Angle ° Angle ° distance

Graph of Data Table C Distance (m) Distance vs. Angle Angle (degrees)

Part 2 So… does the angle of the incline affect the distance? Distance vs. Angle (slope))

Analysis: Does your graph from Data Table A indicate that height of release is directly proportional to the stopping distance? (In other words, does twice the release height give twice the stopping distance? Check your graph to see) In terms of ENERGY, (PE, KE and total) interpret your results from the graph of Data Table C – How did the angle of the ramp relate to the stopping distance of your marble. Explain. Describe why we are able to calculate the Kinetic Energy of the ball (Data Table B) even though we did not know the velocity of the ball at each location. 4. What happens to (KE) energy as the marble rolls on the carpet? 5. Although we did not measure or calculate the velocity of the marble, how would the SPEED of the marble compare at the bottom of the ramp each time you changed the angle in Part 2? (*use the equation s = d x t to guide your thinking).

Energy quiz

Now you play! http://www.gamegecko.com/game/594/ramps Ramps Game! http://www.gamegecko.com/ramps.php