 Work is a force applied through a distance.  So in order for work to be done the object must move.  Work(J) = Force(N) x distance(m)  1Joule = 1 Nm

You push a refrigerator with a horizontal force of 100 N. If you move the refrigerator a distance of 5 m while you are pushing, how much work did you do? DataFormulaWorkAns W=W = F x d F= d= Complete Problems #1-4 for a grade

 Power is the rate at which energy/work is converted.  The rate at which you can do work, or expend energy.  Equation Power = Work time Units = J/s = Watts

 A 13 W lightbulb transforms 13 J of electrical energy into radiant energy each second  A typical person can develop power of only about 500 W for a jump. This would result in a jump that is less than 1 m high for a person with average mass

You transform 950 J of chemical energy into mechanical energy to push a sofa. If it took you 5.0 s to move the sofa, what has your power? DataFormulaWorkAns Complete Problems for a grade

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 All around us, we couldn’t survive without it  Flash of lightning and thunder (light and sound energy)  A roller coaster (potential and kinetic energy)  Nuclear  Electricity  Heat

 Potential is stored energy resulting from the position of an object in a system. Where does a roller coaster have PE?  There are 3 forms of potential energy Gravitational, Elastic and Chemical.  These all have one thing in common, the position of the object.

 Elastic potential energy is energy that is stored energy by compressing or stretching an object.  Examples- the energy of a stretched rubber band or a compressed spring  Chemical potential energy is stored energy due to the chemical bonds between atoms.  Example – stored energy you get from food, or your car gets from gasoline Complete the Slingshot mini lab

 Result of gravity, mass and height (ex. Apple hanging from a tree, roller coaster at the top of a hill  GPE = mass kg x gravity 9.8 m/s 2 x height m  kg x m/s 2 x m=Joule  Energy is measured in Joules

A 65 kg bungee jumper is about to jump from a tower suspend over a concrete street. What is the jumper’s gravitation potential energy GPE at a point of 233 m above the concrete street? Data FormulaWork Ans GPE=? GPE=mgh m=___ g= 9.8m/s 2 h=___

Calculate the GPE of a 93 kg sky diver who is 550m above the ground DataFormulaWorkAns GPE=?GPE=mgh m=___ g= 9.8 m/s 2 h=___ Work GPE problems in notes for a grade

 Energy that an object has because of it’s motion.  Examples – a person moving, atoms moving, a roller coaster coming down a hill, a football flying through the air, a bungee jumper falling

 KE = ½ x mass x speed squared  KE = ½mv 2  Joule = ½ x kg x m/s  KE depends on speed more than mass

A soccer player with a mass of 60 kg is running at a speed of 3 m/s chasing after a ball. If he gets tripped how much kinetic energy will he have as he is flying through the air? DataFormulaWorkAns KE=?KE= ½ mv 2 Work it m= ___backwards v=___v 2 x m x.5

What is the Kinetic energy KE of a 0.02 kg bullet as it passes through 4 crayons traveling at 300 m/s? DataFormulaWorkAns KE=?KE= ½ mv 2 m=___v2 x m x.5 v=___ As you can see, speed plays a big role in amount of KE not mass Stop! Finish GPE & KE Wks

Mechanical Nonmechanical

 Mechanical is the sum of both potential and kinetic energy in a system  It is energy due to position or movement, it is movement or none movement that you can see.

 Nonmechanical is the sum of potential and kinetic that you can not see  Energy at the atom level, energy that you know exists but you can’t see – Kinetic Theory of Energy

Energy of 1. Thermal/heat energy- energy created by the movement of particles, movement we can’t see 2. Chemical Energy- Consider the ability of your body to do work. The glucose (blood sugar) in your body is said to have "chemical energy" because the glucose releases energy when chemically reacted (combusted) with oxygen

3. Electrical energy- moving electrons due to an electrons attraction to protons 4. Sound Energy- Sound waves are compression waves associated with the potential and kinetic energy of air molecules. Can’t see air moving but I know it has energy.

5. Nuclear Energy – energy at the level of the nucleus. Uranium atoms split and release energy in the form of heat to create electricity. 6. Electromagnetic/Light Energy – Radio, Microwaves, Infrared, Visible light (roy g biv), Ultraviolet, X-ray and Gamma

 Due to the Law of Conservation of Energy, energy can not be created of destroyed. It can only change forms.  That is the reason why the total energy in a system remains the same.  Energy is constantly changing from one form to another like a pendulum or roller coaster.

 Both of these examples represents energy that we can see so it is Mechanical Energy.  Energy transformation that we can not see are Nonmechanical Energy.

Plants obtain energy from the sun in the form of _________ energy and turn it into ______________ energy. What about a lamp? Start energy is____________ which turns into ____________energy. A Remote Control Car? Start energy is ____________ which turns into ___________energy. A toaster oven? Start energy is ___________ which turns into _______ energy.

 You transfer energy from your surroundings to your body when you eat.  The Chemical Potential Energy of food supplies the cells in your body with the energy that they need to function.  Energy from food is measured in Calories (C).

 You have seen descriptions of Calories per serving on food packages.  1 Calorie = 4000 J of energy

 Every gram of fat in food Supplies a person with about 10 C (40,000 J).  Carbohydrates and Proteins each supply about 5 C (20,000 J).

 Everything your body does requires energy.  The number of Calories that you need for different activities depends on your weight, your body type, and your degree of physical activity.