Chapter 12

Question 1

Work

Answer 1

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 2

Power

Answer 2

A quantity that measures the rate at which work is done or energy is transformed

Question 3

Mechanical advantages

Answer 3

A quantity that measures how much a machine multiplies or energy or distance

Question 4

Joule

Answer 4

Equivalent to 1kg*m^2/s^2

SI unit for work

Question 5

Watt

Answer 5

SI unit for power

Question 6

Simple machines

Answer 6

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

Question 7

Compound machines

Answer 7

A machine made of more than one simple machine

Question 8

Lever

Answer 8

One family of simple machines. Hammer to pull out nail

Question 9

First class lever

Answer 9

Have a fulcrum located between the points of application of the input and output forces(hammer)

Question 10

Second class lever

Answer 10

The fulcrum is at one end of the arm and the input force is applied to the other end (wheelbarrow)

Question 11

Third class lever

Answer 11

Multiply distance rather than force. They have a mechanic,a advantage of less than 1.(forearm)

Question 12

Pulley

Answer 12

Another type of simple machine in the lever family.(raising a flag on a flag pole)

Question 13

Block and tackle

Answer 13

Multiple pulleys put together in a single unit

Question 14

Wheel and axle

Answer 14

Made of a lever or a pulley connected to a shaft. (Steering wheel)

Question 15

Inclined plane

Answer 15

Second family of simple machines

Question 16

Wedge

Answer 16

.two inclined planes back to back. (Axe blade)

Question 17

Screw

Answer 17

Inclined plane wrapped around a cylinder.

Question 18

Potential energy

Answer 18

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

Question 19

Kinetic energy

Answer 19

The energy of a moving object due to the objects motion

Question 20

Mechanical energy

Answer 20

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

Question 21

Elastic potential energy

Answer 21

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

Question 22

Gravitational potential energy

Answer 22

The energy that could potentially do work on the apple. (Apple falling from tree because stem breaks off)

Question 23

Nonmechanical energy

Answer 23

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

Question 24

Efficiency

Answer 24

A quantity usually expressed as a percentage that measures the ratio of useful work output to work input

Question 25

Open system

Answer 25

Exchange energy with the space that surrounds them. (Earth-receives energy from sun and radiates some of its own energy out into space)

Question 26

Closed system

Answer 26

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

Question 27

Perpetual motion machine

Answer 27

Machine designed to keep on going forever without any input of energy