Chapter 6: Work and Machines

Efficiency

: a measure of how much of the work put into a machine is changed into useful output work by the machine.

Gear

A(n) is a wheel and axle with the wheel having teeth around its rim.

Energy

is always transferred from the object that is doing the work to the object on which the work is done.

Screw

Like the , the wedge is also a simple machine in which the inclined plane moves through an object or material.

Wedge

: an inclined plane with one or two sloping sides.

Wheelbarrow

A(n) is a second- class lever.

Car Jack

A(n) is an example of a machine that increases an applied force.

Mechanical Advantage

: The ratio of the output force to the input force.

Output Work

The is the product of the output force and the distance over which that force is exerted.

System of Pulleys

A(n) can change the direction of the input force and make the output force larger.

Power

is the rate at which work is done.

Input Work

The is the product of the input force and the distance over which the input force is exerted.

Lever

: a bar that is free to pivot or turn around a fixed point.

Work

the energy transferred when a force makes an object move

Power

the amount of work done in one second

Machine

a device that makes doing work easier

Input Force

force that is applied to the machine

Output Force

The force applied by the machine

Mechanical Advantage

The ratio of the output force to the input force

Screw

an inclined plane wrapped in a spiral around a cylindrical post

Wedge

an inclined plane with one or two sloping sides

Compound Machine

Two or more simple machines that operate together