Chapter 12 Flashcards
Work
Work is done when force causes a change in the position or the motion of an object in the direction of the applied force.
Power
Power is the rate at which work is done, how much work is done in a given amount of time
Mechanical advantage
The ratio between the output force and input force
Joule
1 kg m^2/s^2
Watt
Amount of power required to do one joule of work in one second
Simple machines
Most basic type of machines
Compound machines
Combination of simple machines
Lever
Have a rigid arm that turns around a fulcrum
First class lever
Fulcrum in between in and output forces
Second class lever
Fulcrum at one end, input force at other end
Third class lever
Multiply distance rather than force
Pulley
Lever family, middle point is the fulcrum, fixed pulley has a mechanical advantage of one
Block and tackle
.
Wheel and axle
Pulley or lever connected to a shaft
Inclined plane
Ramp redirects horizontal force upward, spreads work of larger distance
Wedge
Two inclined planes pushed back to back, when forced into something, it spreads force outward, causing the object to separate
Screw
A inclined wrapped around a cylinder
Potential energy
Energy of position, results from relative positions of objects ina system
Kinetic energy
Energy an object has because it is in motion
Mechanical energy
Amount of work an object can do because of the objects kinetic and potential energy
Elastic potential energy
Energy stored in any type of stretched elastic material
Gravitational potential energy
Energy that results from position above the ground
Non mechanical energy
Energy that does not affect motion on a large scale
Efficiency
How much useful work it can do
Open system
Exchange energy within the space that surrounds them
Closed system
When the flow of energy is small enough that it can be ignored
Perpetual motion machines
Designed to keep going without input
