ST/EST 404THE MATERIAL UNIVERSE

CHAPTER 3 NOTES

CHAPTER 3

Different Forms of Energy

(pp. 70-91)

1What is Energy?

Energy is the ability to do ______or affect ______.

The SI unit for energy is the ______(___).

One ______is the energy required to move an object with theforce (weight) of one ______over a distance of one ______.

1 ___ = 1 N  1 m

Energy comes in many forms and from many sources.

Examples:

______energy (battery)  ______energy (iPod)

______energy (Sun) ______energy (glucose)

FORMS OF ENERGY AND THEIR POSSIBLE SOURCES

Form of Energy / Description / Examples of Sources
______/ Energy stored in an object due to it’s compression or extension /
  • Compressed spring
  • ______

______/ Energy resulting from the ordered movement of ______from one atom to another. /
  • ______
  • Battery
  • ______

Thermal / Energy resulting from the random ______of all particles in a substance. /
  • Heating element (radiator, stove)
  • ______
  • ______

Radiation / Energy contained in and transported by ______waves. /
  • Light bulb
  • ______oven
  • Sun
  • ______phone
  • Fire
  • ______
  • ______

______/ Energy stored in molecular ______. /
  • Fossil fuels (wood, oil, gas)
  • ______
  • ______

______/ Energy resulting from the movement of air. /
  • ______

Sound / Energy contained in and transported by ______waves. /
  • Sound
  • ______♫

Hydraulic / Energy resulting from the flow of______. /
  • ______
  • ______

______/ Energy stored in atomic ______. /
  • Nucleus of atoms (uranium, plutonium)
  • ______

______/ Energy produced by the movement of a machine. /
  • Bicycle
  • ______
  • ______

1.1 THE LAW OF CONSERVATION OF ENERGY

Energy ______ is the ______of energy from one place to another.

Energy ______ is the ______of energy from one form to another.

Many energy transformations occur in the transmission and distribution of electricity in Quebec.

When water turns the turbines at the central power station, ______energy is transformed into ______energy. This energy is then transformed into ______energy by a generator. This energy is then transferred (transmitted) along power lines to our houses where various electric devices can transform it into other forms of energy (______(radiators, stove), ______(lamps, computer screen), ______(TV, radio), ______(washing machine, lawnmower, blender).

The Law of Conservation of Energy states that energy cannot be ______or ______; it can only be ______or ______. The total amount of energy in an isolated system always remains ______.

1.2 ENERGY EFFICIENCY

A machine orsystemcan always/rarelyconvert all the energy it consumes into a useful form. Some of the energy is “lost” as ______which escapes into the ______.

  • Only ______% of the energy from gasoline is used to run a car.
  • In an incandescent light bulb, only _____% electrical energy consumed is actually used to produce light.

Energy efficiency is the ______of energy ______by a machine or system that was transformed into ______energy

1.3 THERMAL ENERGY

Thermal energy is the energy______in a substance. It depends on the ______of particles present in the substance and their ______.

3.4 Factors That Affect the Thermal Energy of a Substance

Factor / Change in the factor / Change in Thermal Energy
Quantity of particles / Increase
Decrease
Temperature / Increase
Decrease

Thermal energy can be transferred from an environment where the temperature is ______to an environment where the temperature is ______until the two environments have the ______temperature.

Heat is the transfer of ______energy between two areas with ______temperatures. Heat always passes from the ______to the ______environment.

 Heat always moves from an area with a ______temperature to an area with a ______temperature until the two areas have the ______temperature.

The mathematical relationship between heat and thermal energy is:

THE DISTINCTION BETWEEN HEAT AND TEMPERATURE

We often confuse heat and temperature. When the temperature is high, we say, “It’s hot!” But even frozen substances have the ability to transfer heat to even ______substances.

Temperature only takes into account to the ______of the particles in a substance.

Temperature is a measure of the ______of ______of the particles of a substance.

  • Temperature is measured in ______(oC).

Heat depends not only on the ______of the particles, but also on their ______(number of particles).

  • Heat is measured in ______(__).

THE RELATIONSHIP BETWEEN HEAT, MASS, SPECIFIC HEAT CAPACITY AND TEMPEARTURE VARIATIONS(EST ONLY)

The specific heat capacityis the amount of thermal ______required to raise the temperature of one ______of a substance by one ______Celsius.

The specific heat capacity (c) of water is ______J/goC

The heat (Q) absorbed or released by a substance depends on three things:

  1. the ______of the substance (m) in grams (g)
  2. the ______of the substance (Specific heat capacity - c) in J/goC
  3. the change in the ______of the substance (ΔT = Tf - Ti) in oC

“Queue my cat”

If ΔT is negative, the substance ______thermal energy.

If ΔT is positive, the substance ______thermal energy.

Sample Problem: How much heat is required bring 500 mL of tap water at 15oC to a boil?

1.4KINETIC ENERGY(EST ONLY)

Kinetic energy is the energy an object possesses due its ______.

Examples:

  • A moving curling stone can move another stone by ______it. (Hey, this is Canada, eh?)
  • Running water from a ______can turn a turbine and, in turn, generate ______. (ex. Niagara Falls)

THE RELATIONSHIP BETWEEN KINETIC ENERGY, MASS AND VELOCITY

The kinetic energy of an object depends on its ______and ______.

The ______a marble is and the ______is rolls, the more kinetic energy it has, the ______is its capacity to do ______.

Sample problem: What is the kinetic energy of little Richard’s toy car if it has a mass of 132 g

and travels at 1.5 m/s?

  • If mass is doubled, the kinetic energy ______.
  • If the velocity doubles, the kinetic energy ______.

1.4POTENTIAL ENERGY(EST ONLY)

Potential energy is considered an energy ______because it must first be ______into another type of energy in order to do ______.

Gravitational potential energy is the energy ______of an object based on its ______and it’s ______above a reference surface.

THE RELATIONSHIP BETWEEN POTENTIAL ENERGY, MASS, GRAVITATIONAL FIELD INTESITY, AND HEIGHT

Gravitational potential energy depends on its ______, the intensity of the ______field and the ______of the object above a reference surface.

Sample problem: What is the gravitational potential energy of a 2.5 kg potted plant sitting on top

of a window sill that is 3 meters above the ground?

  • If mass is doubled, the gravitational potential energy ______.
  • If height doubles, the gravitational potential energy ______.

1.6MECHANICAL ENERGY(EST ONLY)

In little Richard’s wind up toy car, ______energy is converted into ______energy (when it’s pulled backwards against the floor) and that ______energy is converted back into ______energy (when the car is let go – ZOOM!)

Mechanical energy is the ______of the kinetic energy and the gravitational potential energy.

The law of conservation of energy states that, in a system ______friction, the mechanical energy always remains ______.

Consider the example of a free- falling object (apple from tree). As it falls toward the ground, its potential energy ______(because it’s loosing ______), but it’s kinetic energy ______(because it’s ______).

Sample problem: A mountain bike rider with a total mass (bike and rider) of 85 kg starts at rest at point A, 200 m above the base of a mountain and descends the slope without pedaling, that is, he just uses gravity to get down the hill. (Assume there is no friction or air resistance.)

a)Calculate the gravitational potential energy of the biker at point A.

b)What is the kinetic energy of the biker at point A? ______

c)What is the mechanical energy of the biker at point A? ______

d)Calculate the gravitational potential energy of the biker at point B.

e)Calculate the kinetic energy of the biker at point B.

f)What is the biker’s speed (v) at point B, 150 m above the base of the mountain?

END OF CHAPTER 3NOTES

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