Chapter 12

Question 1

Power

Answer 1

The rate at which work is done.

Question 2

Mechanical advantage

Answer 2

The ratio between the output force and the input force.

Question 3

Joule

Answer 3

Label for work.

Question 4

Watt

Answer 4

Label for power

Question 5

Simple machines

Answer 5

One of the six basic types of machines, which are the basis for all other forms of machines.

Question 6

Compound machines

Answer 6

A machine made of more than one simple machine.

Question 7

Lever

Answer 7

Bar resting on a pivot and is used to help move things.

Question 8

First class lever

Answer 8

A lever with a fulcrum between the points.

Question 9

Second class lever

Answer 9

A lever where the fulcrum is at one end.

Question 10

Third class lever

Answer 10

They multiply the distance rather than force. They have a mechanical advantage of less than 1.

Question 11

Pulley

Answer 11

Has a wheel and changes the direction of a force applied to the cord.

Question 12

Block and tackle

Answer 12

Consists of ropes and one or more pulley blocks and is a machine used for lifting things.

Question 13

Wheel and axel

Answer 13

A lever or pulley connected to a shaft.

Question 14

Inclined plane

Answer 14

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.

Question 15

Wedge

Answer 15

Functions like two inclined planes back to back.

Question 16

Screw

Answer 16

An inclined plane wrapped around a cylinder.

Question 17

Potential energy

Answer 17

The energy that an object has because of position, shape, or condition of the object.

Question 18

Kinetic energy

Answer 18

The energy of a moving object due to the objects motion.

Question 19

Mechanical energy

Answer 19

The amount of work an object can do because of the objects kinetic and potential energies.

Question 20

Elastic potential energy

Answer 20

The energy stored in any type of stretched or compressed elastic material.

Question 21

Gravitational potential energy

Answer 21

Energy that could potentially do work and is stored.

Question 22

Efficiency

Answer 22

A quantity, usually expressed as a present age, that measures the ratio of useful work output to work input.

Question 23

Open system

Answer 23

Systems that exchange energy with the space that surrounds them.

Question 24

Closed system

Answer 24

When the flow of energy into and out of a system is small enough that it can be ignored.

Question 25

Perpetual motion machine

Answer 25

A machine that keeps going forever without any input of energy.

Question 26

Work

Answer 26

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.

Question 27

Non-mechanical energy

Answer 27

Energy that lies at the level of atoms and that does not affect motion on a large scale.