Оцените презентацию от 1 до 5 баллов!
Тип файла:
ppt / pptx (powerpoint)
Всего слайдов:
56 слайдов
Для класса:
1,2,3,4,5,6,7,8,9,10,11
Размер файла:
2.97 MB
Просмотров:
184
Скачиваний:
0
Автор:
неизвестен
Слайды и текст к этой презентации:
№1 слайд![Bell Ringer What do you think](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img0.jpg)
Содержание слайда: Bell Ringer
What do you think of when you hear the word energy?
(List at least three items in your Bell Ringer)
№2 слайд![Bell Ringer What is another](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img1.jpg)
Содержание слайда: Bell Ringer 10/25
What is another term for the ability to do work?
№3 слайд![Energy Energy The ability of](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img2.jpg)
Содержание слайда: Energy
Energy: The ability of an object to do work
Units: Joules (J)
Types of energy include:
Mechanical: Energy of movement and position
Chemical: Energy stored in chemical bonds of molecules
№4 слайд![Energy Thermal Heat energy](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img3.jpg)
Содержание слайда: Energy
Thermal: “Heat energy” stored in materials at a certain temperature
Nuclear: Energy produced from the splitting of atoms
Radiant Energy: Energy traveling the form of electromagnetic waves
Electric Energy: Energy traveling as the flow of charged particles (i.e. electrons)
№5 слайд![Work Work is done when a task](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img4.jpg)
Содержание слайда: Work
Work is done when a task produces a change in energy
Factors affecting work done:
The application of a force
The movement of the object by that force over a distance
№6 слайд![Bell Ringer How much work is](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img5.jpg)
Содержание слайда: Bell Ringer
How much work is required to lift a 2kg object 2m high?
№7 слайд![Work Therefore Work Force x](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img6.jpg)
Содержание слайда: Work
Therefore:
Work = Force x Distance
W = Fd
Units: Joule (J)
1 J = 1 N.m
Note that work requires a distance
№8 слайд![Bell Ringer What is another](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img7.jpg)
Содержание слайда: Bell Ringer 3/31
What is another term for the ability to do work?
You push a stationary wall with a force of 1000N. How much work was done to the wall?
№9 слайд![Bell Ringer](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img8.jpg)
Содержание слайда: Bell Ringer
№10 слайд![Power How much work is](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img9.jpg)
Содержание слайда: Power
How much work is performed over a period of time
Therefore:
Power = Work / Time
P = W/t
Units: Watts (W) where 1 W = 1 J/s
№11 слайд![Thought Question How many](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img10.jpg)
Содержание слайда: Thought Question
How many
horses are in
one
horsepower?
№12 слайд![Power Power can also be](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img11.jpg)
Содержание слайда: Power
Power can also be converted to units of horsepower (hp)
Note: 1 hp 750 W
№13 слайд![Bell Ringer If Superman, at](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img12.jpg)
Содержание слайда: Bell Ringer
If Superman, at 90kg, jumps a 40m building in a single bound, how much does Superman perform?
If this occurs in 3s, what is his power output?
№14 слайд![Energy The amount of work](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img13.jpg)
Содержание слайда: Energy
The amount of work done by an object does not depend on the path taken
Work depends only on the object’s starting and ending points
As work is done on an object, the object itself gains the opportunity to do work
№15 слайд![Energy For example A](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img14.jpg)
Содержание слайда: Energy
For example:
A bowstring drawn back on a bow
Winding an alarm clock
Raising the arm on a pile driver
All of these objects now have the ability to do work
№16 слайд![Mechanical Energy Mechanical](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img15.jpg)
Содержание слайда: Mechanical Energy
Mechanical Energy: Energy of movement and position
There are two major types of mechanical energy:
Potential Energy: Energy of position
Kinetic Energy: Energy of motion
№17 слайд![Potential Energy](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img16.jpg)
Содержание слайда: Potential Energy
Gravitational Potential Energy: The potential due to elevated positions
P.E. = mass x gravity x height
P.E. = mgh
Recall: weight = mass x gravity
Therefore: P.E. = weight x height
№18 слайд![Potential Energy](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img17.jpg)
Содержание слайда: Potential Energy
№19 слайд![Kinetic Energy Objects in](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img18.jpg)
Содержание слайда: Kinetic Energy
Objects in motion are capable of doing work
KE = ½.mass.velocity2
KE = ½mv2
№20 слайд![Kinetic Energy Note that the](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img19.jpg)
Содержание слайда: Kinetic Energy
Note that the velocity of the object is squared when determining KE
If the velocity of the object is doubled, the KE is quadrupled
№21 слайд![Energy Conservation Energy is](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img20.jpg)
Содержание слайда: Energy Conservation
Energy is constantly transforming, but never “disappears”
Law of Conservation of Energy: Energy cannot be created or destroyed, only changed from one form to another.
№22 слайд![Energy Conservation Potential](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img21.jpg)
Содержание слайда: Energy Conservation
Potential and kinetic energy are constantly transforming back and forth
Most of the time during this transformation, some energy is turned to heat and transferred out of the system
№23 слайд![Energy Conservation](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img22.jpg)
Содержание слайда: Energy Conservation
№24 слайд![](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img23.jpg)
№25 слайд![Bell Ringer Jill has a](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img24.jpg)
Содержание слайда: Bell Ringer
Jill has a velocity of 5m/s. If she has a mass of 60kg, what is her kinetic energy?
If Bob, at 70kg, is standing on top of a 13m high hill. What is his potential energy?
№26 слайд![Work-Energy Theorem The](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img25.jpg)
Содержание слайда: Work-Energy Theorem
The change in gravitational potential energy of an object is equal to the amount of work needed to change its height
Therefore:
Work = PE
Fd = mgh
№27 слайд![Work-Energy Theorem The KE of](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img26.jpg)
Содержание слайда: Work-Energy Theorem
The KE of a moving object is equal to the work the object is capable of doing while being brought to rest
Therefore:
W = KE or Fd = ½mv2
№28 слайд![Work-Energy Theorem Putting](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img27.jpg)
Содержание слайда: Work-Energy Theorem
Putting these two ideas together gives us the general Work-Energy Theorem:
If no change in energy occurs, then no work is done. Therefore, whenever work is done, there is a change in energy.
№29 слайд![Bell Ringer List and give an](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img28.jpg)
Содержание слайда: Bell Ringer
List and give an example of the 6 types of simple machines.
№30 слайд![Simple Machines Machine A](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img29.jpg)
Содержание слайда: Simple Machines
Machine: A device used to multiply forces or to change the directions of forces
There are six types of simple machines:
Pulley: Grooved wheels which assist in raising, lowering, or moving an object
№31 слайд![Simple Machines Lever A stiff](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img30.jpg)
Содержание слайда: Simple Machines
Lever: A stiff bar which pivots on a support to assist in lifting or moving an object
Wedge: An object consisting of a slanting side ending in a sharp edge which separates or cuts materials apart
Wheel and Axle: A wheel with a rod through its center which lifts or moves objects
№32 слайд![Simple Machines Inclined](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img31.jpg)
Содержание слайда: Simple Machines
Inclined Plane: A slanting surface connecting a lower level to a higher level
Screw: An inclined plane wrapped around a rod which holds objects together or lifts materials
№33 слайд![Bell Ringer What is an](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img32.jpg)
Содержание слайда: Bell Ringer
What is an example of a 100% efficient machine?
№34 слайд![Mechanical Advantage](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img33.jpg)
Содержание слайда: Mechanical Advantage
Mechanical Advantage: A machine’s ratio of output force to input force
№35 слайд![Efficiency Efficiency A](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img34.jpg)
Содержание слайда: Efficiency
Efficiency: A machine’s ratio of useful work output to total work input
№36 слайд![Efficiency Ideal machines](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img35.jpg)
Содержание слайда: Efficiency
Ideal machines have 100% efficiency
This means that all of the energy put into the machine exits as useful energy
All other machines will ALWAYS have an efficiency of less than 100%
A machine cannot output more work than is put into it
№37 слайд![Pulleys Single Pulley Changes](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img36.jpg)
Содержание слайда: Pulleys
Single Pulley:
Changes the direction of a force exerted by a rope or cable
System of pulleys:
Multiplies input forces, creating large output forces
№38 слайд![Pulleys Each supporting](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img37.jpg)
Содержание слайда: Pulleys
Each supporting strand of rope holds an equal fraction of the weight
Tension in this cable is the same throughout its entire length
Input force = tension in each supporting segment of the cable
Mechanical advantage = number of supporting strands
№39 слайд![Pulleys](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img38.jpg)
Содержание слайда: Pulleys
№40 слайд![Pulleys](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img39.jpg)
Содержание слайда: Pulleys
№41 слайд![Bell Ringer How many](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img40.jpg)
Содержание слайда: Bell Ringer
How many supporting strands are there ?
What is the Mechanical advantage here equal to?
What is the input force required to lift the 200kg object?
№42 слайд![More Practice What is the](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img41.jpg)
Содержание слайда: More Practice
What is the minimum effort that must be applied to lift the load?
For every 2 meters the rope is pulled through what height does the load rise off the ground?
What is the mechanical advantage?
№43 слайд![LEVERS](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img42.jpg)
Содержание слайда: LEVERS
№44 слайд![Levers A simple machine made](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img43.jpg)
Содержание слайда: Levers
A simple machine made of a bar which turns about a fixed point
Fulcrum: The pivot point of a lever
Change the direction of or multiply input forces
№45 слайд![Three Types of Levers Type](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img44.jpg)
Содержание слайда: Three Types of Levers
Type 1 Lever: Fulcrum lies between the input force and the load
i.e.) A seesaw
Type 2 Lever: The load lies between the fulcrum and the input force
i.e.) A pry bar
№46 слайд![Three Types of Levers Type](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img45.jpg)
Содержание слайда: Three Types of Levers
Type 3 Lever: The input force lies between the fulcrum and the load
i.e.) Your forearm pivoting about your elbow
№47 слайд![Lever Lab](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img46.jpg)
Содержание слайда: Lever Lab
№48 слайд![Levers If friction is small](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img47.jpg)
Содержание слайда: Levers
If friction is small enough to neglect:
Work Input = Work Output
or
(Fd)input = (Fd)output
Therefore: A small input force over a large distance will output a large force over a small distance
№49 слайд![Levers](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img48.jpg)
Содержание слайда: Levers
№50 слайд![Levers](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img49.jpg)
Содержание слайда: Levers
№51 слайд![Wedge Wedge An object](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img50.jpg)
Содержание слайда: Wedge
Wedge: An object consisting of a slanting side ending in a sharp edge which separates or cuts materials apart
i.e. knife
№52 слайд![Wheel and Axel Wheel and Axle](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img51.jpg)
Содержание слайда: Wheel and Axel
Wheel and Axle: A wheel with a rod through its center which lifts or moves objects
ie: Cart
№53 слайд![Inclined Plane Inclined Plane](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img52.jpg)
Содержание слайда: Inclined Plane
Inclined Plane: A slanting surface connecting a lower level to a higher level
i.e. Accessibility ramp
№54 слайд![Screw Screw An inclined plane](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img53.jpg)
Содержание слайда: Screw
Screw: An inclined plane wrapped around a rod which holds objects together or lifts materials
№55 слайд![Compound Machine Compound](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img54.jpg)
Содержание слайда: Compound Machine
Compound machines use two or simple machines to complete a task
Examples?
Rube Goldberg Device
№56 слайд![Bell Ringer How much energy](/documents_6/0c6e9f37a968b16d48fdb97cf43d0e29/img55.jpg)
Содержание слайда: Bell Ringer
How much energy is transferred in lifting a 5 kg mass 3m?
What is the work energy theorem?