2.8 Work, Energy & Machines

Last lesson of this unit!

• "Surprise" quiz on Friday! - On paper...

• Quiz will be on lessons 2.5-2.8.

• All HW/assignments for this week are due Friday

  LETS START OFF WITH SOME REVIEW QUESTIONS

.

Multiple Choice

TRUE OR FALSE;

There's no quiz on Friday

• FALSE

• TRUE

Multiple Choice

State the unit of energy

• Kilograms

• Newtons

• Joules

• KiloJoules

Multiple Choice

Which of the following is not a source of energy for the body?

• Animals

• Chocolate

• Bread

• Sleeping

Multiple Choice

Complete the sentence

If you take in (eat) more energy than you need ............

• Your body stores it as fat to use in the future

• You excrete the excess food

• You have more energy to do work, play, and function better

• All of these

Multiple Select

What is energy? (Select two answers)

• The ability to do work

• The capacity to cause change

• The rate of doing work

• The unit of work

Open Ended

State the law of conservation of energy.....

Multiple Select

Which of the following are correct interpretations of the law of conservation of energy..... (select all that apply)

• Energy cannot be created or destroyed, only transferred from one form to another

• The total amount of energy in the universe is always constant

• Energy is always conserved

• The total amount of energy before an event is equal to the total amount of energy after an event

Multiple Choice

Most energy is wasted in the form of ...

• Electrical energy (from over use of appliances)

• Chemical energy from excess food

• Thermal energy (Heat)

• Sound energy from loud noises all around

Multiple Choice

Energy dissipation means .....

• storing energy

• saving energy

• wasting energy

• none of these

Multiple Choice

The average kinetic energy of the molecules of a substance is known as....

• Heat

• Temperature

• Energy transfer

• Convection

Multiple Select

What does thermal equilibrium mean? (Select two answers)

• Two objects in contact reach the same temperature

• Temperature difference between two objects in contact is 0

• When heat flows from a hot to cold object

• When heat flows from a cold to hot object

Multiple Select

The energy you need to increase the temperature of a material depends on (select 3 answers)

• The mass of the material

• The color of the material

• The temperature inrease you want

• What the material is made of

Multiple Choice

Heat is transferred by ___ in solids, by ___ in fluids, and by ___ in the absence of particles

• Conduction, radiation, convection

• convection, conduction, radiation

• radiation, convection, conduction

• conduction, convection, radtiation

• convection, radiation, conduction

Multiple Choice

Which of the following is not a fossil fuel?

• Coal

• Turbines

• Oil

• Gas

Multiple Choice

What is power, and what unit is it measured in?

• Power is the ability to do work,

  Measured in Watts

• Power is the rate of energy transfer.

  Measured in Watts

• Power is the rate of doing work,

  Measured in Joules per hours

• Power is the how fast energy changes

  Measured in Newtons

2.8 Work, Energy & Machines

Use pages 154-155 to complete this lesson worksheet.

Lesson objectives; At the end of this lesson, you should be able to;

• Calculate the work done.

• Apply the conservation of energy to simple machines.

Multiple Select

What are today's lesson objectives?

• Calculate the work done.

• Apply the conservation of energy to simple machines.

• Calculate the power

• Apply energy to simple machines

Multiple Choice

Page 154;True or false?

Riding uphill on a bicycle is easier to do in a lower gear..

• TRUE

• FALSE

Multiple Choice

Page 154; Complete the sentence;

Not all energy transfers are to do with heating and cooling, you can transfer energy by ......

• ..moving faster

• ...doing pushups

• ...avoiding wastage

• ...doing work

Multiple Choice

Page 154; Complete the sentence;

When you slide the book....

• ..you do work against friction

• ...you do work against gravity

• ...you do work against the earth

• ..you do work

Multiple Choice

Page 154; Complete the sentence;

Work Done = ____ X ____

• Force x distance

• Force x density

• Force x diameter

• Force x degrees

Multiple Select

Page 154; Complete the sentence;

Simple machines ...... (Select all that apply)

• Make it easier to lift, move, or turn things

• Reduce the force that you need to do a job

• Increase the distance that something moves when you apply a force

• Provide extra energy to simplify work

Multiple Choice

Page 154; TRUE or false?

A lever is work multiplier.

• TRUE

• FALSE

Multiple Choice

Page 154; Complete the sentence;

When you lift a book....

• ..you do work against friction

• ...you do work against gravity

• ...you do work against the earth

• ..you do work

Multiple Choice

Which of the following is not a lever?

Multiple Choice

When using a lever, the work is simplified because...

• The small force is applied over a large distance

• The force is applied over a small distance

• The force is equal to the distance

• All of these

Multiple Select

Page 155; Which of the following are true about gears on a bicycle system.

• ..it is a simple machine

• ..they are like levers that are rotating

• ...you can use them to increase the force.

• ...you can use them to change direction

• ...you can use them to go faster

Multiple Choice

Page 155; Complete the sentence;

A small force acting over a big distance...

• ..produces a small force

• ..produces a big force

• ..produces no force

• ..produces a big distance

Multiple Choice

Page 155; Complete the sentence;

A big force can only move

• ..a big distance

• ...a big object

• ...a small distance

• ...a small object

Multiple Choice

In all systems, you cannot get more energy than you put in because...

• We're not that strong

• you cannot get something for nothing

• it violates the law of conservation of energy

• all of these

Multiple Choice

A simple machine does work with

• No energy

• An electric current

• One motion

• Heat

Multiple Choice

The transfer of energy that occurs when force makes an object move.

• Energy Transformation

• Kinetic Energy

• Potential Energy

• Work

Multiple Choice

Energy is not created or destroyed, only transformed.

• Newton's 3rd Law

• Law of Conservation of Mass

• Law of Conservation of Energy

• Law of Conservation of Motion

Multiple Select

Select all that apply to a rollercoaster at the top of the hill.

• High Kinetic Energy

• Low Kinetic Energy

• High Gravitational Potential Energy

• Low Gravitational Potential Energy

Multiple Select

Select all that apply to a rollercoaster at the bottom of the hill.

• High Kinetic Energy

• Low Kinetic Energy

• High Gravitational Potential Energy

• Low Gravitational Potential Energy

Multiple Select

What is energy?

• The ability to work

• Electrical currents

• The ability to create change

• The ability to move

Multiple Choice

work is measured in .............

• Joules

• newton

• meter

• Second

Multiple Choice

Calculate work done on an object by a force equal 10 Newton and moved for 2 meters

• 12

• 20

• 28

• 36

Multiple Choice

Calculate force needed to move an object 5 meter if the work done is 10 joules

force = work / distance

• 2 newton

• 15 newton

• 10 newton

• 0 newton

Multiple Choice

calculate force if work =1,000 and distance =10

force = work / distance

• 80

• 10000

• 100

• 22

Multiple Choice

what is the product of force and displacement?

• work

• power

• energy

Multiple Choice

if you push a cart with a force of 60 N for 2 m... how much work have you done

• 120 J

• 30 J

• 120 N

• 30 N

Multiple Choice

Fill in the blank:

The formula for Work is....W = F x ___

• D, depends

• D, depth

• D, diameter

• D, distance

Multiple Choice

The formula for Work is....W = F x D, what does F stand for?

• Fight

• Force

• Forward

• Foreign

Multiple Choice

You are moving a couch across the living room. The couch weighs 420 N and you need to move it 6 meters. Calculate the work.

• 420 j

• 2520 j

• 2400 j

• 1600 j

Multiple Choice

Newtons are the correct unit for which of the following?

• Force

• Work

• Power

• Acceleration

Multiple Choice

The rate at which work is done.

• Joules

• Power

• Watts

• Newtons

Multiple Select

How do you calculate power? (Select two answers)

• P = W/t

• P = E/t

• P = w * t

• P = bbq/chicken

Multiple Choice

It took 500 Newtons of force to push a car four meters in 10 second. How much power was exerted?

• 200 Watts

• 125 J

• 200 J

• 500 J

Poll

I feel comfortable with my understanding of....

• Energy

• Work

• Power

• Energy Transfer

• Energy Transformation

Poll

I'm ready for the surprise quiz on Friday

• No way, postpone to next year please!

• Need to review all my lesson quizziz answers (2.5-2.8)

• Might need to look at few things tomorrow

• Totally

ENJOY YOUR DAY OFF TOMORROW