Chapter 12- Vocab Flashcards
Work
Work is 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.
Power
A quantity that measures the rate at which work is done or energy is transferred.
Mechanical advantage
A quantity that measures how much a machine multiplies force or distance.
Joule
The label for work
Watt
The SI unit 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
Levers have a rigid arm and a fulcrum. Levers are divided into three classes: first class, second class, and third class levers
First class lever
All first class levers have a fulcrum located between the points of application of the input and output forces.
Second class lever
The fulcrum is at one end of the arm and the input force is applied to the other end.
Third class lever
Multiply distance rather than force. As a result, they have a mechanical advantage of less than 1.
Pulley
Pulleys are modified levers.
Wheel and axle
Is a lever or pulley connected to a shaft
Inclined plane
Multiply and redirect force. An inclined plane turns a small input force into a large output force by spreading the work put over a large distance.
Wedge
A modified inclined plane. A wedge functions like two inclined planes back to back.
Screw
A screw is an inclined plane wrapped around a cylinder.
Potential energy
The energy that an object has because of the position, shape, or condition of the object.
Kinetic energy
The energy of a moving object due to the object’s motion.
Mechanical energy
The amount of work an object can do because of the object’s kinetic and potential energies.
Elastic potential energy
The energy stored in any type of stretched or compressed elastic material, such as a spring or bungee cord.
Gravitational potential energy
The energy that could potentially do work results from its position above the ground is called gravitational potential energy.
Nonmechanical energy
Energy that lies at the level of atoms and that does not affect motion on a large scale
Efficiency
Effiecency is the ratio of useful work out to work in. Efficiency is usually expressed as a percentage. The efficiency of a machine is a measure of how much useful work it can do.
Open system
Open system exchange energy with the space that surrounds them.most systems are open systems.
Closed system
When the flow of energy into and out of a system is small enough that it can be ignored, the system is called a closed system.
Perpetual motion machine
A machine designed to keep on going forever without any input of energy. These theoretical machines are called perpetual motion machines.
Block and tackle
Multiple pulleys put together in a single unit.
