8Th Science Work And Machines-Ch.12

Front 1

When you exert a FORCE ON AN OBJECT that causes it to move, it is called ?

Back 1

WORK

Front 2

There is no work without ____?

Back 2

motion

Front 3

Work = _____x _____

Back 3

force
distance

Front 4

A Joule= what?

Back 4

one newton meter

Front 5

A unit of work is what?

Back 5

the amount of work you do when exert a force of 1 Newton to move an object a distance of 1 meter

Front 6

The force required to accelerate 1kilogram of mass at 1 meter per second is called ?

Back 6

Newton or a UNIT OF FORCE

Front 7

A device with which you can do work in a way that is easier or more effective is called what?

Back 7

A MACHINE

Front 8

How does a machine make work easier?

Back 8

By changing the amount of roce you exert and the distance or direction in you exert force

Front 9

The force you apply to the machine is called?

Back 9

INPUT OR EFFORT FORCE

Front 10

The force applied by the machine is called?

Back 10

OUTPUT FORCE OR RESISTANCE FORCE

Front 11

For tools to be a machine it must do one of more of what 3 things?

Back 11

1.multiplying force - output must be greater than input force. (ex: a lever, inclined plane)
2.multiplying distance- allows you exert force over shorter distance. (ex:hocky stick,rake,)
3. change directions-just change the direction of the force

Front 12

The number of times a force applied to a machine is MULTIPLIED BY THE MACHINE is called?

Back 12

mechanical advantage

Front 13

What is the formula for mechanical advantage?

Back 13

MECHANICAL ADVANTAGE=OUTPUT/INPUT

Front 14

When the mechanical advantage is greater than 1 what happens?

Back 14

More force comes out of the machine than is put into the machine

Front 15

What is the Mechanical Advantage of changing direction?

Back 15

Input and output are same
Mechanical advantage is 1
Force in different direction

Front 16

Efficiency of Machines staes that what happens?

Back 16

1. Output work is less
2. Input work is more
3. compared they equal a percentage

Front 17

Formula for calculating Efficiency is what?

Back 17

Output divided by input work x 100 % = efficiency

Front 18

What is actual mechanical advantage?

Back 18

the mechanical advantage of a machine is a REAL LIFE SITUATION

Front 19

What is ideal mechanical advantage?

Back 19

the advange of a machine without FRICTION. input and output are equal= 100%

Front 20

A simple machine that is flat, with slanted surface is?

Back 20

Inclined plane

Front 21

You exert force with an inclined plane over a ______ distance?

Back 21

longer

Front 22

What is the advantage formula of an incline plane?

Back 22

length of incline divided by height of incline

Front 23

The efficiency of an inclined plane is conncected to work lost due to ______?

Back 23

friction

Front 24

What is a device that is thick at one end and tapers to a thin edge at the other end?

Back 24

WEDGE

Front 25

What is an inclined plane wrapped around a cylinder?

Back 25

screws

Front 26

What are ridgid bars that are free to pivot, rotate about a fixed point?

Back 26

LEVERS

Front 27

What is the fixed point on a lever which ALLOWS IT TO pivot?

Back 27

FULCRUM

Front 28

How do you calculate the ideal mechanical advantage of a lever using the distances between the forces and the fulcrum.

Back 28

DISTANCE from fulcrum to input force DIVIDED BY distance from fulcrum to output force.

Front 29

What is a 1st class lever?

Back 29

Distance from fulcrum to input force is GREATER than distance from fulcrum to the ouput force

Front 30

Examples of 1st class lever?

Back 30

seesaw, pliers, scissors, crowbar

Front 31

Can a 1st class lever change the direction of the input force?

Back 31

Yes

Front 32

Second class levers always _____ force?

Back 32

multiply

Front 33

Do second class levers CHANGE DIRECTION?

Back 33

NO

Front 34

What are examples of 2nd class levers?

Back 34

Wheelbarrow, nutcracker, bottle opener

Front 35

____ class levers multiply distance but don't change direction of the input force?

Back 35

3rd

Front 36

What are examples of third class levers?

Back 36

shovels, baseball bats, boat paddle

Front 37

What is a simple machine that is made of 2 circular or cylindrical objects are fastened together and theat rotate about a common axis?

Back 37

WHEEL AND AXLE

Front 38

What are the advantages of the wheel and axel?

Back 38

Multiplies the force but over a longer distance

Front 39

How do you calculate the ideal mechanical advantage of the wheel and axel.

Back 39

Use the radius of the wheel divided by the radius of the axle

Front 40

What does the variation of the wheel and axle produce?

Back 40

If you apply force on the axle then the input force is applied over a short distance and the output forcer is over a long distance

Front 41

What kind of machine is a grooved wheel with a rope wrapped around it. ?

Back 41

PULLEY

Front 42

By pulling on the rope of a pulley you can change the ____and _____of the input force

Back 42

amount
direction

Front 43

When you have a ___ pulley this changes the direction of the force only?

Back 43

fixed

Front 44

Does a fixed pully multiply the force?

Back 44

no

Front 45

A fixed pulley had the mechanical advantage of ____#

Back 45

one

Front 46

Moveable pulleys in force in the ____ direction as the output force.

Back 46

same

Front 47

Moveable pulleys ideal advantage is #____

Back 47

2

Front 48

The output force is greater or lesser than the input force?

Back 48

Greater

Front 49

Name a pulley system?

Back 49

Block and Tackle

Front 50

What is the ideal advantage of the block and tackle?

Back 50

It is equal to the number of sections of the rope that supports the object.

Front 51

A machine that utilizes 2 or more simple machines is a ____ ______.

Back 51

Compound Machine

Front 52

Describe a geer or system of geers?

Back 52

toothed wheels that fit into one another

Front 53

Most of the machines in your body are ______?

Back 53

levers

Front 54

Tendons are tough ______ tissue than connects _____ to ___.

Back 54

connective tissue
muscles
bones