Do Now: 02/04/2014 What is the equation used to solve each of the following: Work = Power = A force of 100 N is used to move an object 15 meters in 60 seconds. Find the work done and the power it took to move the object.

Objectives: Learning Intentions – Success Criteria – Students will be able to apply their knowledge of work and power to the activity of running up stairs Success Criteria – We will know we are successful when we can calculate the most powerful student in the class based on the work and power of running up a flight of stairs

Activity Do you think you are the most powerful student in this class? Lets find out! Today we are doing an activity where we will figure out the work and power it takes to run up a flight of stairs

Directions: FIRST: Calculate the force of each group member Weight X 0.45 = mass Mass X 9.8 = Force Start working on Work and Power Problems on page 2 One group at a time will go into the stairwell and record the distance and the time it takes to run the stairs for each group member Return to the classroom and calculate the work and power of each group member

What to Do: Lab sheet due to me by the end of the class period! First graded assessment of second semester!

Questions: Calculate the work and power for each of the members in the data table Who did the most work? Who was the most powerful?

Questions from Activity 3. How could you increase the amount of work that a person had to perform as they climbed the stairs?   4. How could you increase the amount of power that a person had as they climbed the stairs?

Wed., 02/05/2014 Do Now: 1. Yesterday you did the following calculation as part of the pre-lab: Mass = Weight in lb. X 0.45 What is the unit of mass calculated above? 2. You also calculated: Force = mass (calculated above) X 9.8m/s2 In your own words, what is this force?

Objectives: Learning Intentions – Students will be able to identify the different types of energy Students will be able to explain that energy is conserved and transferred from one type to another Success Criteria – We will know we are successful when we can accurately determine the different types of energy involved in energy transformations

Energy Energy: The ability to do work. Examples: chemical energy, electrical energy, energy of motion, heat energy

Unit of Energy: A joule (J) is the S.I. unit of measurement for energy What else do we measure in joules?

Main Types of Energy Mechanical Nuclear Electrical Radiant Chemical

Some forms of energy Mechanical energy is the energy possessed by an object due to its motion or its position. Potential energy and kinetic energy are both forms of mechanical energy.

Some forms of energy Chemical energy is a form of energy stored in molecules. Batteries are storage devices for chemical energy.

Some forms of energy Electrical energy comes from electric charge, which is one of the fundamental properties of all matter.

More forms of energy Nuclear energy is a form of energy stored in the nuclei of atoms. In the Sun, nuclear energy is transformed to heat that eventually escapes the sun as radiant energy.

More forms of energy Radiant energy is energy that is carried by electromagnetic waves. Light is one form of radiant energy.

Heat Energy Heat is energy that is transferred by differences in temperature.

Conservation of Energy Systems change as energy flows and changes from one part of the system to another. Each change transfers energy or transforms energy from one form to another.

Conservation of Energy The idea that energy transforms from one form into another without a change in the total amount is called the law of conservation of energy. The law of energy conservation says the total energy before the change equals the total energy after it.

Practice: 1. 2. 3. 4.

Practice: Complete the energy practice problem.

Do Now: 02/06/2014 List at least 3 different types of energy that we discussed yesterday.

Objectives Learning Intentions – Students will be able to distinguish between potential and kinetic energy Students will be able to calculate potential and kinetic energy Success Criteria – We will know we are successful when we can accurately determine the potential and kinetic energy of a scenario or situation

Energy Energy: the ability to do work  Unit: Joule (J) -Energy can change forms

Mechanical energy Mechanical energy is the energy possessed by an object due to its motion or its position. Mechanical energy = Potential Energy + Kinetic Energy

2 Types of Mechanical Energy Potential Energy Kinetic Energy

Potential energy Objects with potential energy are able to exert forces (exchange energy) as they change position. Potential energy is energy due to position.

PE = mgh Potential Energy mass of object (kg) height of object (m) (joules) PE = mgh gravity (9.8 m/sec2)

Potential Energy The person has more potential energy at the top of the stairs than at the bottom.

Potential Energy If we dropped an egg from the 2nd floor and the 3rd floor, which would have more potential energy?

Potential Energy Example # 1: If your egg has a mass of 2 kg, how much potential energy does it hold at a height of 10 meters?

Calculate Potential Energy A rock weighs 1000 N. What is its potential energy if it located on a shelf that has a height of 5 meters? Looking for: PE Given: weight = mg = 1000 N; height = h = 5 m Relationship: PE = mgh Solve: PE = 1000 N x 5 m = 5000 J (remember 1 J = 1 N x m)

Do Now: Friday, 02/07/2014 What is the ‘energy of position’? What is the formula to calculate potential energy (PE)?

Kinetic energy Kinetic Energy: energy of motion Depends on: mass, speed

Kinetic energy Energy of motion is called kinetic energy. A moving cart has kinetic energy because it can hit another object and do work.

Kinetic Energy Which has more kinetic energy, the regular car at 40 mph or the race car at 120 mph? The race car has more KE because it has a higher speed.

Kinetic Energy Which would hurt more, getting hit by a 15 foot wave or a 2 foot wave? The bigger wave would hurt more because even though they travel at the same speed, the bigger wave has more mass.

Calculating Kinetic Energy Kinetic Energy (KE) = ½mv2 Mass (in kg) Velocity (in m/s) or speed

Kinetic Energy Example # 3: The bird has a mass of 2 kg. It is flying at a speed of 5 m/s. Find its kinetic energy.

Independent Practice Complete the practice problems on your own or with a partner Questions, ask! We will go over some problems together at the end of class Completed sheets should be in your class tray to get credit!

Practice: Determine the amount of potential energy of a 5.0 N- book that is moved to three different shelves on a bookcase. The height of each shelf is 1.0m, 1.5m, and 2.0m. Potential energy at 1.0 m _________________________ Potential energy at 1.5 m _________________________ Potential energy at 2.0 m _________________________

Practice: A 1.0 kg ball is thrown into the air with an initial velocity of 30 m/s. How much kinetic energy does the ball have?   How much potential energy does the ball have when it reaches the top of its ascent?

Practice: You are on skates at the top of a small hill. The height of the hill is 1.7 meters. The last time you checked, your mass was 60.kg. What is your weight in Newtons?   What is your potential energy at the top of the hill?

Do Now: 02/11/2014 What is the potential energy of a 65 kg climber on top of Mount Everest, which is 8800 m high? Calculate the kinetic energy of a 2473 kg car moving at 29 m/s.

Objectives: Learning Intentions Success Criteria – Students will be able to apply their knowledge of work, energy and machines to the assessment Success Criteria – We will know we are successful when we can accurately complete the assessment on work, power, energy and machines

Quiz Work Power Energy You can use your notes – but must complete independently Talking = failing