14.1 Work and Power
14.2 Work and Machines
14.3 Mechanical Advantage and Efficiency
14.4 Simple Machines
Key concepts
100

The SI unit of work is the __?

The Joule

100

A machine is a device that changes a ___?

Direction or magnitude

100

The IMA equals the ratio of the input distance to the output ___?

Output distance

100

What are the six types of simple machines?

Lever, Wheel and Axle, Inclined Plane, Wedge, Screw, and Pulley

100

What is a joule equal to?

1 Newton-meter

200

The SI unit of power is the ___?

The Watt

200

The force that is exerted on a machine is called the ____ force.

Input force

200

Because of friction is always present, the AMA is always ____ than the IMA.

Less than 

200

Two or more simple machines working together make up a ____?

Compound Machine

200

1hp = how many watts

746 watts

300

The watt and the horsepower are both units of ___?

Power

300

The work input equals the input force multiplied by the input ___.

Input distance 

300

The ____ of a machine is the number of times that the machine increases the input force.

The mechanical advantage (MA)

300

The IMA of a third-class lever is always greater than, equal to, or less than?

Less than

300

Any part of a force that does not act in the direction of an object's motion does no ___ on an object?

No work

400

The rate at which work is done is called __?

Power

400

A ____ changes the size of a force needed, the direction of a force, or the distance over which a force acts.

Machine

400

The AMA equals the ratio of the output ___ to the input force.

Output force

400

Screws with threads that are closer together have a ___ IMA?

Have a greater IMA

400

You calculate work by multiplying the force acting in the direction of ___ by the distance the object moves.   

The force

500

For work to be done on an object, the object has to ____?

Move in the direction of that force

500

The distance the output force is exerted through is the ___ distance.

Output distance 

500

The IMA of a machine is the mechanical advantage in the absence of ___?

Friction

500

The IMA of a pulley system is equal to the number of rope sections supporting the load being lifted. True or False?

True

500

A ____ can be described as an inclined plane wrapped around a cylinder?

A screw