5th Six Weeks Review

POTENTIAL ENERGY

&

KINETIC ENERGY

REVIEW

The Law of Conservation of Energy

Energy can not be ________ or ________ it can only be converted from one form of energy to another.

The total amount of energy in the universe remains ________!

created destroyed

constant

Revisiting Newton’s 3rd Law of Motion

Newton’s 3rd law states that for every ____________ force there is an equal and opposite ____________ force.

ACTION

REACTION

Newton’s 3rd Law of Motion

Newton’s 3rd Law of Motion

A student throws a ball while standing on a skateboard. Which direction will the student go after he releases the ball?

A.

B.

C.

Potential Energy

Potential energy is ___________ energy waiting to be ______________.

STORED

RELEASED

The man and the apple both have potential energy due to position.

GPE = mass X 9.8 m/s2 X height

Gravitational Potential Energy

Rate of acceleration due to gravity. All objects falling under the force of gravity, will fall at 9.8 m/s2.

Gravitational Potential Energy

Gravitational Potential Energy

KINETIC ENERGY

KINETIC ENERGY IS ENERGY THAT IS IN ______________.

K.E. = mass x velocity2

2

K.E. = m X v2

2

What has a greater affect of kinetic energy, mass or velocity? Why?

The velocity does because its value is squared

MOTION

Which has more kinetic energy, a large dog sitting on a sidewalk or a small cat running down the street?

a. The large dog

b. The small cat

c. Both have the same kinetic energy

d. Need more information to answer

THERMAL ENERGY REVIEW

Energy moves from a hotter to a colder object by one of the three mechanisms:

1. Conduction2. Convection3. Radiation

Conduction is the transfer of thermal energy through matter by the DIRECT contact of particles.

Heat energy

SOLIDS are most effective at conducting heat because their particles are closer together.

Convection is the transfer of thermal energy in a FLUID by the movement of the heated particles.

Liquids are fluids. HOT liquid is less dense so it RISES, COLD liquid is more dense so it SINKS.

Gases are fluids. HOT gas is less dense so it RISES, COLD gas is more dense so it SINKS.

Radiation is the transfer of thermal energy by electromagnetic waves that can travel through space even when no matter is present.

FIRE

A lizard uses radiant energy to help control

body temperature

QUICK REVIEW

Show me what you have learned!

The heat provided by the heating system warms up the room primarily by _________.

A.Conduction

B.Convection

C.Radiation

Thermal energy is transferred from the pot to spoon by ________.

A.Conduction

B.Convection

C.Radiation

Thermal energy is transferred from the sun to “Vacation Santa” by _________.

A.Conduction

B.Convection

C.Radiation

RENEWABLE RESOURCES

&

NONRENEWABLE RESOURCES

A renewable resource is an energy source that is REPLACED nearly as quickly as it is used.

Wind

Sun

WaterFEW POLLUTUTANTS

A nonrenewable resource is an energy source that CAN NOT be REPLACED by natural processes as quickly as they are used.

oCoal

oPetroleum

oNatural GasMANY POLLUTUTANTS

Solar cell

WORK & SIMPLE MACHINES

REVIEW

Work is the transfer of energy that occurs when a force makes an object move.

Work = Force X distance

W = F X d

F d

W

Calculate the work needed to lift a TV weighing 6 newtons a distance of 2 meters.

F d

W

6 2

W 12 Joules

X

If a weight lifter is holding barbells above his head, what does he have

to do to perform work?

A.stand still

B.move barbells sideways

C.step forward

D.lower barbells

Power is the amount of work done in a certain amount of time. It is the rate at which work is done.

P t

W

X

Power = Work / time

P = W / t

How much power is required to do 10 joules of work in 5 seconds?

P t

W

P 5

10

2 Watts

Efficiency is the measure of how much of the work put into a machine is changed into useful output work by the machine.

Work output is ALWAYS less than work input!

Efficiency = (work output / work input) X 100%

Efficiency = (Wout / Win) X 100%

Efficiency = (Wout / Win) X 100%

Efficiency = (80 / 320) X 100%

Efficiency = 25%

All machines are less than 100% efficient. Some energy is converted to thermal energy due to _________.

a. position

b. mass

c. friction

d. speed

The human arm is an example of which class of lever?

A.First class

B.Second class

C.Third class

D.None of the above

A see saw is which class of lever?

A.First class

B.Second class

C.Third class

D.None of the above

Which lever Which lever requires the requires the LEAST effort LEAST effort

to lift the to lift the load?load?

The CLOSER the fulcrum is to the load, the easier it is to lift!

Mechanical AdvantageCalculating the mechanical advantage of an

inclined plane.

IMA = length of slope / height of slope

IMA = l / h

Length of Slope

Height of Slope

What is the ideal What is the ideal mechanical advantage mechanical advantage of this inclined plane?of this inclined plane?

a)a)840840b)b)4848c)c)33d)d)1/31/3

Length of Slope

Height of Slope

12 m4 m

IMA = l / h

IMA = 12 / 4

IMA = 3

REVIEWING…….

Archimedes’ Principle

Bernoulli’s Principle

Pascal’s Principle

Archimedes’ principle states that the buoyant force on an object is equal to the weight of the fluid displaced by the object.

Buoyant force is the upward force exerted on an object by the fluid that it is immersed in.

Why does the rock Why does the rock in water weigh less in water weigh less than the rock in air?than the rock in air?

Bernoulli’s principle states that as the velocity of a fluid increases, the pressure exerted by the fluid decreases.

According to Bernoulli, the faster a fluid flows According to Bernoulli, the faster a fluid flows the less pressure it exerts. In the diagram the less pressure it exerts. In the diagram above, where is the air flow the slowest?above, where is the air flow the slowest?

A)A)On the top On the top

B)B)On the bottom On the bottom

C)C) Top and bottom are the same Top and bottom are the same

LOW pressure area

HIGH pressure area

Pascal’s principle states that pressure applied to a fluid is transmitted throughout the fluid.

Gas Laws Review

Boyle’s Law

Charles’ Law

Boyles’ Law

Volume (size of container) Pressure

Volume (size of container) Pressure

Gas particles will have MORE space to move around, so LESS pressure

Gas particles will have LESS space to move around, so MORE pressure

As the volume increases (y) the pressure decreases (x)

Charles’ Law

Temperature Volume

Temperature Volume

Put a balloon in oven it will increase in

volume

Put a balloon in freezer it will

decrease in volume