Chapter 4

Question 0

What is the formula for power

Answer 0

Work divided time

Question 1

What is the formula for work

Answer 1

Force times distance

Question 2

What is power measured

Answer 2

Watts

Question 3

What is force measured

Answer 3

Joules

Question 4

What is the definition of work

Answer 4

When a force causes an object to move in the direction of the force

Question 5

Is pushing as stalled car work. Why

Answer 5

No because the cat isnt moving

Question 6

If you pick a suitcase up and move forward is it work? Why?

Answer 6

No because the suitcase isn’t going in the same direction as the force

Question 7

Where r u doing more work

1) lifting a 80N barbell
2) lifting a 160N barbell

Answer 7

You don’t know until you know how high each one is lifted

Question 8

What is the definiton of power

Answer 8

Rate at which work is done

Question 9

Machine defition

Answer 9

Device that makes work easier by changing the size and direction

Question 10

Input force

Answer 10

The force you apply

Question 11

Output force

Answer 11

The work the machine applies

Question 12

Can work out put ever be greater then work input

Answer 12

No

Question 13

What is mechanical advantage

Answer 13

How many times a machine multiplies your force

Question 14

Do machines save work

Answer 14

No

Question 15

What do machines change

Answer 15

Size of force and distance

Question 16

With a machine increases the force what happens to the distance

Answer 16

It decreases

Question 17

When machines change the direction of the force what is the mechanical advantage

Answer 17

1

Question 18

What is the mechanical advantage of a machine that has a greater input force

Answer 18

Less than 1

Question 19

Why is work output of a machine always less then the work input

Answer 19

Because if friction so the machine loses work

Question 20

Mechanical efficency

Answer 20

Comparison of machines work output with the work input

Question 21

What is the equation for mechanical efficiency

Answer 21

Work output divided by work input times hundred

Question 22

Ideal machine

Answer 22

A machine with 100 percent efficency

Question 23

What are the six simple machine

Answer 23

Lever, incline plane, wedge, screw, wheel and axle, and pulley

Question 24

Lever

Answer 24

Simple machine consisting of a bar that pivots at a fixed point called a fulcrum

Question 25

What are levers used for

Answer 25

Apply force to the load

Question 26

First class lever

Answer 26

The fulcrum is between the input force and the load

Question 27

What do first class levers fo

Answer 27

Change the direction of the input force

Question 28

List one example of a first class lever

Answer 28

Teeter totter

Question 29

Second class lever

Answer 29

Load is between the fulcrum and input force

Question 30

How do second class levers help

Answer 30

Allow you to apply less force then the force exerted by the load

Question 31

Third class lever

Answer 31

The input force is between the fulcrum and load

Question 32

What do third class levers do

Answer 32

They don't increase input force

Question 33

Mechanical advantage of a first class lever

Answer 33

Greater then one

Question 34

Whatis the mechanical advantage of a second-class lever

Answer 34

Greater than one

Question 35

What is the mechanical advantage of a third class lever

Answer 35

Less than one

Question 36

Incline plane

Answer 36

A straight slanted surface

Question 37

How are inclined planes helpful

Answer 37

requires a smaller input force

Question 38

What happens the distance with an inclined plane

Answer 38

The distance increases

Question 39

Mechanical advantage of incline plane

Answer 39

The longer the inclined plane is compared with its height the greater the mechanical advantage

Question 40

How do you calculate the mechanical advantage of an inclined plane

Answer 40

Divided length by height

Question 41

wedge

Answer 41

Double inclined plane that moves

Question 42

How are wedges helpful

Answer 42

Which is applying an output force that is greater then your input force

Question 43

What happens to the distance with the wedge

Answer 43

It increases

Question 44

Example of wedge

Answer 44

Knife

Question 45

Mechanical advantage of wedge

Answer 45

The longer and thinner the wedge is the greater the mechanical advantage

Question 46

How do you calculate the mechanical advantage of the wedge

Answer 46

Length divided by thickness

Question 47

Screw

Answer 47

Incline plane wrapped in a spiral

Question 48

Mechanical advantage of screwa

Answer 48

The longer the incline plane the greater the mechanical advantage and when u straighten it out it is a really long incline plane

Question 49

Wheel and axle

Answer 49

Simple machine consisting of two circular objects of two different sizes

Question 50

What is bigger wheel or axle

Answer 50

Wheel

Question 51

Mechanical advantage if wheel and axle

Answer 51

Can be determined by dividing the radius of the wheel by the radius of the axle and turning the wheel makes a mechanical advantage of greater than one

Question 52

Pulley

Answer 52

Grooved wheel that holds a rope or a cable

Question 53

Fix pulley

Answer 53

Doesnt increase force

Question 54

Movable pulley

Answer 54

Doesn't change forces direction and you have to make both sides move

Question 55

Block and tackles

Answer 55

Fixed pulley and moveable pulley together can have large mechanical advantage when several pulleys are used

Question 56

Compound machines

Answer 56

Made of two or more compound machines

Question 57

Some examples of compound machines

Answer 57

Block and tackle, scissors, and zipper

Question 58

Mechanical efficiency of a compound machine

Answer 58

Mechanical efficiency of compound machine is low because the more moving parts a machine has the less mechanical efficiency and friction should be reduced as much as possible