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1/10

Unit Conversion

Back

= 1

cm

Continue

then

Step 3: Identify unit conversion factors. These are the Linking Units.

Unit Conversion Process

300

There are a few things to keep in mind when you are working on a unit convervsion problem.
You can multiply any number by 1 without changing its value:

and

100 cm

1 m100 cm

Step 4: Cancel units and do the math (multiply, divide).

Starting
Units

If

100 cm
100 cm

1 m

100 cm
1 m

Step 5: Does the result make sense?

Step 1: Identify the unit you have. These are the Starting Units.

Desired
Units

1 m
1 m

2/10

3 m

Unit conversion is a multi-step process that involves:multiplying/dividing by a numerical factorselecting the correct number of significant digitsrounding

Step 2: Identify the unit you want. These are the Desired Units.

= ?

mph to km/h

m2 to ft2 to acres

Quiz

m3 to yds3

W/m2 to hp/in2

hp to Watts

(g x in)/sec2 to N

psi to N/m2

rpm to deg/sec

Frequency (hertz) is one of the 22 derived SI units:

=

6

Identify starting units

second

And a full rotation is 360 degrees (a 360 means spinning completely around 1 time):

1 hertz =

Identify desired units

Revolutions per minute (rpm) measures the number of times an object rotates around an axis in a unit of time (a measure of frequency). Degree per second is a measure of angular frequency (rotational speed). Click each button to work thru the conversion process.

X

Element
with Audio
HTML

Conversion factor: 360 / 60 =

drag and drop the linking units below to cancel out starting units

1 revolution

60 revolution

= 30

360 degrees

Problem: convert 5 rpm to deg/sec

minute

5

Linking Units

We know ther are 60 seconds in 1 minute:

?

degree

60 seconds

Starting Units

revolution

rpm to deg/sec

1 minute

Desired Units

Identify conversion units

Cancel units

Conversion factor: 550 x 1.3558 =

? W

550 ft-lbs
sec

Horsepower is a unit of measurement of power. Its calculation is based on the power needed to move 550 pounds one foot in one second. A Watt can be expressed in terms of SI base units as the work or energy per unit time.

745.7

Problem: Convert 25 hp to Watts

Convert the Desired Units to SI Units

= 18,642.5 W

25

click to continue

1 J/s

Desired Units

A horse can sustainably perform work at a rate of 550 foot-pounds per second.

1 ft-lb

Starting Units

The ft-lb is a unit of work used in the U.S. The joule is the SI unit of energy and represents work done when a one-newton force is applied ofer a distance of one meter.

1 foot

1 W

1 second = 1 joule per second = 1 watt

550 lbs

1.3558 J

hp

1 hp

Place the remaining Linking Units

745.7 W

W

1,155,836.19

144 in2

m2

500

= 577,918,097

10.7639 ft2

12 inches = 1 ft, so 144 in2 = 1 ft2

1 ft2

You are working on a project that involves designing a high-performance engine. The power output of the engine is specified as 500 hp/in2. However, you need to convert this power density to watts per square meter to ensure its compatibility with the system you are integrating it into.

1 horsepower (hp) = 745.7 watts (W)

1 m2

1 meter = 3.28084 ft, so 1 m2 = 10.7639 ft2

in2

Conversion factor: 144 x 10.7639 x 745.7 =

4.44822 N

You are working on an engineering project involving a pneumatic system. The pressure measurement you have is 85 psi, but you need to convert it to N/m2 to ensure compatibility with the existing system specifications. The pascal describes a unit of pressure or force applied to an area. PSI is a measure of pressure commonly used in the U.S.

Conversion factor: 4.44822 x 144 x 10.763911 =

10.7639 ft2

6894.76

1 lbf

We know there are 144 square inches in 1 square foot:

lbf

N

psi to N/m2

= 586,054.6 N/m2

One pound-force is equal to about 4.44822 newtons

And 1 meter equals 3.28084 ft, so 1 square meter equals 10.7693 square feet:

85

m2

hour

20

43,560 ft2

An acre is a unit of area commonly used for measuring land in the U.S, but you are negotiating with a Canadian company that uses square meters.

10.7639 ft2

There are 3.28084 feet in 1 meter, so there are 10.7639 square feet in 1 square meter

Conversion factor: 43560 / 10.7639 =

1 Acre

Acres

4046.86

The most common shape for Acre is 600 ft x 66 ft

Identify starting units

= 80,937.21

Conversion factor: 35.3147 / 27 =

And there is 3.28084 feet in a meter, so 1 cubic meter is 35.3147 cubic feet.

1 m3

1.31

640

You need to order cement to cover an area that is 80 m in length by 80 m in width by 10 centimeters high. To convert to m3, multiply 80 m x 80 m x 0.1 m.

27 ft3

= 838.4 yd3

35.3147 ft3

We know that there are 3 feet in a yard, so there are 27 cubic feet in a cubic yard.

yd3

1 yd3

m3

m3 to yds3

= 0.0771

1000 g

12 in

We know there are 3.28084 feet in 1 meter:

g*in

We know that 12 inches are in 1 foot:

1 kg

And 1 kg is 1000 grams:

s2

Conversion factor: 0.08333 x 0.3084 x 0.001 =

1 ft

kg*m

Newton’s Second Law of Motion states that Force = mass x acceleration (F = ma). Force is expressed in newtons: one newton (1N). You are conducting a drop test on a mobile device and the data collected is provided in g*in/s2. You need to covert the data to its SI equivalent, the newton (N).

0.0000257

3000

3.28084 ft

kilometer

Miles per hour is a unit of measurement. It is the number of miles traveled in one hour. Kilometers per hour is a unit of measurement using length in kilometers and time in hours.

1 meter

Meter (m) is one of the 7 SI units:

55

.001 km

= 89.595

Conversion factor: .001 / 3.28084 x 5280 =

And 1 mile is 5,280 feet:

mile

5280 ft

Problem: convert 55 mph to kph

1.609

1 mile

1 min

5/10

1 degree/s = 0.16667 revolution/min

550 ft-lbs
sec

1 Hz

60 s

Convert deg/sec to rpm

1 HP

1 Acre

1 in

1 square meter = 0.0002471054 Acre

1 in2

1 yd

Convert m2 to Acres

660 ft x 66 ft

10.7639 ft2

8/10

1 yd2

Convert Watts to Horsepower

Hp

7/10

1 W

1 pound

1 ft-lb

1 Watt = 0.00134102 horsepower

1.3558 J

1 s

1 g

.01 km

Convert km/h to mph

1 mi

1 m2

1 J

9/10

1 km/hr = 0.621371 mi/hr

1 ft

5280 ft

745.7 W

144 in2

Convert hp/in2 to W/m2

1 Watt per square meter = 0.000000865174 hp per square inch

4/10

1 lb

Convert N/m2 to psi

10/10

1 N

1 Newton/square meter = 0.000145038 pound-force per square inch

4.44822 N

600 ft x 60 ft

1 yd3

27 ft3

1 ft2

Convert yds3 to m3

1 cubic yard = 0.76454858 cubic meter

3/10

1 in3

35.3147 ft3

g*in

1 kg

6/10

1 kilogram meter per second squared = 39370.0787 gram inch per second squared

Convert kg*m/s2 to g*in/s2

1 lbf = 4.44822 N

1 J/s = 1W

1 acre = 600 ft x 60 ft

1 ft-lb = 1.3558 J

1 hp = 500 fl-lbs/s

1 m = 3.28084 ft

Now convert each scenario in the opposite direction using the information learned in the previous scenarios:

1 mi = 5280 ft

1 Hz = 60 revolutions/min

1 hp = 745.7 W

1 revolution = 360 degrees