deck 10 Flashcards
science
What is work?
Work occurs when you exert a force on an
object that causes the object to move some
distance.
What is power?
Power the rate at which work is done.
What are simple machines?
Machines help by making work easier.
To make work easier, you can reduce the input force
What are the 6 simple machines?
inclined plane, wedge, screw, lever,
wheel & axle, and pulley.
What are inclined plane, wedge, screw, lever,wheel & axle, and pulley.?
Inclined plane = flat sloped surface
Wedge = two inclined planes (back to back)
that can move; produces two output forces
Screw = an inclined plane wrapped around a cylinder.
Levers = rigid bar that pivots/rotates on a fixed point.
Fulcrum = fixed point that a lever pivots
around.
Wheel & Axle: two circular/cylindrical objects that are connected together and rotate around a common axis, where
Pulley: a grooved wheel with a rope (cable)
wrapped around it.
Fixed Pulley: pulley attached to a structure
(ceiling, wall). Fi = Fo , change in direction; MA = 1
Movable Pulley: pulley attached to moving object.
increase Fo , no change direction; MA = 2
Block & Tackle: fixed & movable pulley system.
increase Fo , no change direction; MA = varies
Types of Levers:
First Class Lever: Fo F Fi change force direction; as fulcrum close to Fo , Fo increases
Example: scissors, pliers, seasaw
Second Class Lever: Fi Fo F
same force direction; as fulcrum close to Fo , Fo increases
Example: doors, nutcracker, bottle opener
Third Class Lever: Fo Fi F
same force direction; as fulcrum close to Fi , Fo decreases
Example: fishing pole, shovel, baseball bat
what are compound machines.
Compound Machine: a combination of two or more simple machines.
What is mechanical advantage?
Mechanical Advantage (MA): the number of times a machine increases the input force (Fi).
What is efficiency?
Efficiency: compares output work to input work. An ideal machine’s efficiency = 100%. A real machines efficiency is less than 100% because some output work (Wo) is lost due to friction (heat loss).
what is energy?
Energy: ability to do work
What are the types of energy?
Chemical: from chemical bonds
Electrical: moving electrons
Mechanical: moving things (parts)
Heat: moving molecules
Nuclear: from atom’s nucleus
Light (Solar): moving photons
Sound: vibrating objects
Potential: stored energy-PE = weight (mass) x height
Kinetic: motion energy-KE= 0.5 mass x velocity2
what is energy transformation and conservation?
energy conservation=Energy can not be created or destroyed but can only change form
energy transformation=light-chemical
electrical-thermal
chemical-mechanical
chemical-mechanical
What is nonrenewable energy?
Renewable Resources: are materials that
can be replaced at the rate at which we use them.
What is renewable energy?
Nonrenewable Resources: are materials
that can not be replaced at the rate at which we use them.
