Physics: Energy, Work and Simple Machines Flashcards
Efficiency
can be calculated by comparing a machine’s output work to its input work
Machine
A device that changed the magnitude or direction of a force
Compound Machine
Consists of two or more simple machines linked so that the resistance force of one machine becomes the effort force of the second machine
Resistance Force
The force exerted by a machine
Watt
A unit of power defined as 1 joule per second
Effort Force
The force exerted by a person on a machine
Work-energy theorem
States that the work done on an object equals the change in kinetic energy of the object
Energy
The ability of an object to produce a change in itself or its surroundings
Kinetic energy
The energy that results from the motion of an object
Power
The rate of doing work
Mechanical advatage
The ratio of resistance force of a machine to its effort force
Joule
The SI unit for work
Ideal Mechanical Advantage
To calculate you compare the effort distance to the resistance distance
Work
When an applied force is multiplied by the distance through which the force is applied
Equation for finding work
W=fd
Work and energy are measured in
Joules
Explain the relationship between work and energy
They’re equal according to the work-energy theorem
Equation for finding power
w/t
Power
the rate of energy transfer
In what unit is work measured in
joules
In what unit is power measured in
watts
If an area has flowing water and has money to build a dam to connect it to the electricity grid, then they can use this form of renewable energy
Hydroelectric
This type of energy is produced when electricity generators are placed on the surface of the ocean. The energy provided is most often used in desalination plants, power planes, and water pumps
Waves
This type of energy is created by hot spots; areas where earth’s core heat comes to surface
Hydrothermal and Geothermal
This source is often compared compared to batteries; both convert the energy produced by a chemical reaction into usable electric power
Hydrogen Fuel Cells
This source of energy is used for powering low voltage devices that are not used often. Its life and endurance is dependent on the apparatus it will energize an the chemical agten involved in its makeup.
Conventional Batteries
This type of energy is used throughout areas of the Midwest and in the southern regions of the US and can be a way to generate power to large areas in a fairly inexpensive way.
Wind turbines/generators
This source can be made from scraps of plants, grain, wood, and other types of biological material; it converts a solid to a liquid form to use instead of gas in vehicles
Biomass
This type of energy relies on steller energy; splitting of heavy atoms and the combining of lighter oens
Nuclear energy
Converting landfill hasses into a source of renewable energy is beneficial because it reduced greenhouse gas emissions and can generate revenue from the sale of the electricity
Indirect Natural Gas
This type of energy is significant because our society uses large amounts of it and it depends on the use of power plants that convert some other kind of energy into it
Standard Electrical Power
This device absorbs light energy from the sun and converts it into usable forms of energy
Solar Cells
A bone is like a
lever
A muscle contraction is like a
force
Joints are like
the fulcrum
The resistance is like
the weight of body or lifted object
Two inclined planes placed back to back
wedge
A circular lever that consists of a grooved wheel rotating about a hub
pulley
any slanting surface
inclined plane
an inclined plane wrapped around a cylinder
screw
A fixed wheel turning on a rod through its center
wheel and axle
A rigid bar that rotates on a pivot called a fulcrum
levers
First class lever
FUlcrum is in the middle (EFL) seesaw, hammer removing nail
Second class lever
the load is in the middle (ELF) paper cutter
Third class lever
the effort is in the middle (FEL) rake
WHy is gasoline called a “miracle” in the film
can go far with little amount easily refilled, cheap
WHat makes electric cars still exesnive
Batteries are expensive
What are 2 major advantages of natural gas as an energy source compared to the other fossil fuels
Natural gas is less expensive, environmentally friendly, burns cleaner
Do you think nuclear power is a safe form of energy
Yes, it has gotten a lot safer, they’re more secure and can withstand drastic weather
What does the film say that you and I do to help the global energy demand
Suggest nuclear, natural gas, and renewable energy can be combined to see 50 year crossover
Why is the documentary called “Switch?”
They’re looking to switch old energy sourced to more environmental and future friendly
What are two factors that can influence the price of any type of energy
Supple and demand, natural disasters
