Chapter 12 Flashcards
Power
The rate at which work is done.
Mechanical advantage
The ratio between the output force and the input force.
Joule
Label for work.
Watt
Label for power
Simple machines
One of the six basic types of machines, which are the basis for all other forms of machines.
Compound machines
A machine made of more than one simple machine.
Lever
Bar resting on a pivot and is used to help move things.
First class lever
A lever with a fulcrum between the points.
Second class lever
A lever where the fulcrum is at one end.
Third class lever
They multiply the distance rather than force. They have a mechanical advantage of less than 1.
Pulley
Has a wheel and changes the direction of a force applied to the cord.
Block and tackle
Consists of ropes and one or more pulley blocks and is a machine used for lifting things.
Wheel and axel
A lever or pulley connected to a shaft.
Inclined plane
They multiply and redirect force. They turn a small, input force into a large output force by spreading the work out over a large distance.
Wedge
Functions like two inclined planes back to back.
Screw
An inclined plane wrapped around a cylinder.
Potential energy
The energy that an object has because of position, shape, or condition of the object.
Kinetic energy
The energy of a moving object due to the objects motion.
Mechanical energy
The amount of work an object can do because of the objects kinetic and potential energies.
Elastic potential energy
The energy stored in any type of stretched or compressed elastic material.
Gravitational potential energy
Energy that could potentially do work and is stored.
Efficiency
A quantity, usually expressed as a present age, that measures the ratio of useful work output to work input.
Open system
Systems that exchange energy with the space that surrounds them.
Closed system
When the flow of energy into and out of a system is small enough that it can be ignored.
Perpetual motion machine
A machine that keeps going forever without any input of energy.
Work
The transfer of energy to a body by the application of a force that causes the body to move in the direction of the force.
Non-mechanical energy
Energy that lies at the level of atoms and that does not affect motion on a large scale.