Kinetic and Potential Energy

1. Kinetic and Potential Energy LBSC 642 Final Project Second Semester 2010/2011 Margaret Buck and Rick Kahley

2. Kinetic and Potential Energy Target Group – 9th grade Introduction to Chemistry and Physics Class Three Class Lesson Plan Student math skills at Algebra One

3. Kinetic and Potential Energy Lesson One

4. What do these have in common?

6. Play U-Tube Video of Hydroelectric Dam. Demonstrates conversion of potential to kinetic energy. Discuss how water’s potential energy was created. http://www.youtube.com/watch?v=cEL7yc8R42k&feature=related

7. Play U-Tube Video of Controlled Building Demolition. Demonstrates conversion of potential to kinetic energy. Discuss how building potential energy was created. http://www.youtube.com/watch?v=7Ng5qwtR59A&feature=related

8. Skate Board Park - U of Colorado. http://phet.colorado.edu/en/simulation/energy-skate-park Discuss relationship to potential and kinetic energy Discuss real skateboard safety

9. Work and Power Notes Work: Work is the product of a _ (force) _______ applied and the _ (distance) __________ an object moves in the direction of the force _ (Force) __________ is measured in Newtons (N), and _ (distance) _____________ in meters (m) We call the units of work a _ (Joule) _______ (J)

10. Example: A force of 96 N is applied in lifting a concrete block 1.5 meters. How much work is done in lifting the block? W = F x d W = 96 N x 1.5 M W = 144 Joules (J) Work is only done when the force is in the __________ direction as the motion of the object.

11. Power: • power (P) is the rate at which you do _ (Work) ________ • it is the amount of work done per unit of _ (time) _______ • we measure work in _ (Joules) ______ and time in __ (seconds) __________. • the unit of power is the _ (watt) _______, or one Joule per second • large quantities of power are given in _ (kilowatt – kw) _____________. • to calculate power, take the _ (Work) _________ done divided by the _ (time) _________ it takes to do the work. P = W/T

12. Example: A set of pulleys is used to lift a boat weighing 990 N. The boat is lifted 2 meters in 55 seconds. How much power is used? W = F x D W = 990 N x 2m W = 1,980 Joules P = W/T P = 1,980 J/55sec P = 36 watts

13. Class work Problems • A horse named Greg pulls a cart of wood a distance of 12 meters using a force of 43 Newtons. How much work has the horse done? • Matt pushes his car with a force of 5 N; however, the car does not move. How much work has Matt done? • Chris pushes his can with a force of 5 N and the car rolls a total of 8.6 m. How much work has Chris done?  • Katherine lifts a 7.3 N object and puts it on a shelf 2.4 m high. How much work has she done? •  Lindsay holds a 6.4 N chair exactly 1.9 meters off the floor for 26 seconds. How much work does she do? •  Stephanie pushes a chair 3.6 meters across the floor using a force of 2.2 N. How much work does she do?

14. Conservation of Energy Lab See upload

15. Kinetic and Potential Energy Lesson Two

16. Energy • Two Forms of Energy: _ (Kinetic) ______ and _ (Potential) __________. • Kinetic Energy is energy of _________________. Examples include a plane traveling through the air, a girl running a race or a cyclist rounding a curve. • The formula for kinetic energy is KE = ½ mv2 • Example: Calculate the kineticenergy in a car moving at 10 m/sec if the car has a mass of 1200 kg? KE = ½ mv2 KE = ½ (1,200 kg) (10m/sec)2 KE = ½ (1,200 kg) (100m2/sec2) KE = 60000 Joules (J)

17. Potential Energy is referred to as __ (stored) _______ energy. In general it is not moving or is in a position where it can, but is not, doing ___ (Work) __________. Examples include a book on a shelf, a stretched rubber band or water behind a dam. • The formula for potential energy is PE = m x g x h • Example: Calculate the potentialenergy of a car on a hill 100 meters high, if the car has a mass of 1200 kg? PE = m x g x h PE = 1,200 Kg x 9.8 m/sec2 x 100 m PE = 1,200,000 Joules (J)

18. Determine if the following situations have mostly potential or kinetic energy, by placing an “X” in the column next to the situation.

20. Insert screen shot here of Roller Coaster Physics Video Cover

21. Roller Coaster Physics – Viewing Guide • What aspects of roller coasters scare people or give them a thrill? • Scientific “Work” is done when a force moves an object. When is Work done on a roller coaster? • What type of energy does the roller coaster have at the top of the first large hill, kinetic or potential? • What type of energy does the coaster have at the bottom of the first large hill? • Define “g” force • Define positive “g” force. What does it feel like to the rider? • Define negative “g” force. What does it feel like to the rider

22. Energy Problems – Class work • A ball rolling across a table has a velocity of 3.5 m/sec. If the mass of the ball is 0.57 kg, calculate the KE of the ball.  • A 212 kg car is traveling at 63 m/sec. Calculate the KE of the car.  • A 65 kg crate is lifted 45 meters into the air. Calculate the potential energy of the crate in comparison to its starting point. • If a four car roller coaster weighs 1,500 kg including people how much energy is required to raise it from its starting position to a height of 120 m, the top of the first hill.? Your answer should be in Joules. • If the roller coaster in #4 above moves from a dead stop to the top of the hill in 35 seconds how much power is required? (Hint: Remember P = W/t)

23. Kinetic and Potential Energy Lesson Three

24. Skate Park still starts here and then moves to computer lab. Demo first Provide students handouts of guided exercises on simulation Discuss real skateboard safety

25. Small group work • Demonstrate how to build tracks that generate high kinetic energy and low kinetic energy models. • Lab as partial assessment

26. Alternative if computer lab not available…. • Teacher demo in class room. • Students selected at appropriate times to “assist” teacher with simulation

27. Final assessment to include opening quiz on Day Three and Simulation Exercises in Computer Lab • End with Safety reinforcement