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Work, Energy, and Power. What is energy?. Energy – the ________ to do _________. Every source of energy you can think of fits the above definition. List three: 1) _________________ 2) _________________ 3) _________________. Work. What is work?
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What is energy? • Energy – the ________ to do _________. • Every source of energy you can think of fits the above definition. List three: • 1) _________________ • 2) _________________ • 3) _________________
Work • What is work? • Work – Definition has ____ parts in physics. • 1) A ______ must have been exerted. • 2) The object being worked on must have ______ or ________.
If I push the wall as hard as I can, is work being done to the wall? • _______________ • Thought process: • Did the wall ________? Did the wall _______? • If the answer to both of those is “no”, then no work was done.
If I push a desk around, was work done to the desk? _______ • If you sit in your desk to take a quiz, is work being done to the desk? _______ • If you squeeze a ball of play-doh, was work done to the play-doh? ________ • If you fold a piece of paper on the desk, was work done to the paper? _____ To the desk? _______
There are _______ formulas for calculating work. • The first formula: W = F x d • W = work • F = Force • D = displacement. • Remember, the “W” is big, because little “w” means “weight.”
Force x displacement in units would be _______ x _______ • The ______ is ___ x ____. • ____ is our unit for work.
THE CATCH!!!!! • The ______ and ________ in the formula have to be in the same _________.
Is work done to the box when it’s pushed along the table? ________ • Is work done to the box when it’s picked up? _____ • Is work done to the box if I hold it? _______ • Is work done to the box if I hold it and walk to the left? _________
The SECOND formula for Work is: • W = m x g x h. • W = work, m = mass, g = gravity, h = height. • Part of this formula is m x g. What was m x g the formula for? _______________ • So this formula can also be written as: • W = _____ x ______.
W = F x d is for “________ work.” • ___________ work is the work done by machines. • W = m x g x h is for “work against _______”. • This is work done whenever the object is moved _________, or against _________.
Power • We compare strengths of work by comparing it’s __________. • We abbreviate this with a capital “____.”
Your formula for calculating Power is • P = W • T • Powers often ________ different objects. • Example: Power for cars is measured in _________.
Inclined Plane • An inclined plane is a ramp that connects a ________ level (usually the ground) to an ________ level. • In fancy physics words, inclined planes turn ________ ________ ________ into ______ ______.
The W = F x d (mechanical work) is the work done by ________ something _______ the ramp. • The W = m x g x h (or W = w x h, work against gravity) would be done by ________ something ________ the ramp.
The mechanical work will ALWAYS _______ the work against gravity in the calculations.
For the Lab • What were you doing work against when you were walking up and down the stairs?
Energy • Energy is the _______ to do _________. • That means energy causes ________ that cause _______ or _______.
Work-Energy Theorem • BUT when work is done to _______ it creates energy! • So _______ creates ________, and ________ creates __________. • This is called the ______-_______ Theorem.
Because of the theorem, both work and energy are measured in _______. • An machine that creates mechanical work from energy is a ________. • An machine that creates energy from mechanical work is a __________.
Different Types of Energy! • __________ energy is energy from things in motion. • __________ energy is energy that’s being stored from objects at rest. • There are different types of these energies, too! Lets draw them!
To Calculate GPE • GPE = m x g x h. • GPE = Gravitational Potential Energy • m = _______ • g = ________ • h = _________. • This is the same formula as the ________ ________ ________ formula!
Calculating Translational Kinetic Energy • TKE = ½ m x v2 • m = _______ • v = ________
Law of Conservation of Energy • Energy can neither be _______ nor _______. • Energy can go back and forth between _______ and _______, but the total amount of energy will always be the same. • So when asked to find the total energy ______ all the numbers.
________ of energy for earth comes from _________. That causes all the wind, weather, ocean currents, photosynthesis, and the processes by which we get fossil fuels. Only ______ of earth’s energy comes from geothermal heat/volcanos, or earth’s rotation.
