UNit Conversion

[learner27]

Hello. IM here to ask how to convert this Km\hr to Miles\seconds

yeah i know you will refer me to google but i already did that but i cant find articles that can answer me clearly thanks guys!

so all in all

HOw to convert compound units?

thanks

[Iota]

1km = 0.621371192 miles

1 hour = 60 seconds minutes.... there's the stupid mistake, and hopefully the only one.

Conversion factors ^

When converting compound units, you convert one at a time, e.g. convert km into miles, and then hours into seconds.

 

I think you might want meters per second though.

Edited July 24, 2012 by Iota

[learner27]

no it is stated on the problem that we hace to convert from given unit to miles...

 

sir can i ask...

for example i will convert 40km/h to miles...

should it be 24.84miles/sec?

[alpha2cen]

Unit conversion of equations is more complex.

[learner27]

actually the whole problem is written on the "Homework" page named "Problem Solving"

hope you can help me guys

[CaptainPanic]

Iota, 1 hour = 3600 seconds.

 

40 km/h = 24.84 miles / hour, because 40 km = 24.84 miles

 

24.84 miles / hour = 24.84 miles / 3600 seconds, because 1 hour = 3600 seconds.

 

... and 24.84 miles/ 3600 seconds = 0.006904 miles / second

 

 

 

Alternatively, you can do it the other way around too: first the time units, then the distance.

 

40 km/h = 40 km / 3600 seconds = 0.01111 km/s

 

0.01111 km/s = 0.006904 miles/second

[JMJones0424]

[math] \frac{40km}{1 hour} \cdot \frac{0.62 miles}{1km} \cdot \frac {1 hour}{3600 sec}[/math]

 

 

[math] \frac {0.0069 miles}{sec}[/math]

[learner27]

OHH ! so thats how! you need to divide it ! thank you!

[alpha2cen]

actually the whole problem is written on the "Homework" page named "Problem Solving"

hope you can help me guys

 

Such methods give you no help. As possible as , you'd better do it by yourself.

[learner27]

thank you but, what if the problem is not asking for the conversion km/s to miles only?

should i ignore the seconds?

[JMJones0424]

lets say you're converting 100km/s to miles.

 

 

[math]\frac {100km}{1sec} \cdot \frac {0.62 miles}{1km} = \frac {62 miles}{sec}[/math]

[Iota]

.

Edited July 24, 2012 by Iota

[learner27]

ohh thank you!

[Iota]

Didn't realise others had posted, just follow their nice and simple answers. Without the mistake of saying there are 60 seconds in an hour ahahahah. Oh God.

[learner27]

thats ok sir, i finally understand it thank you so much for all the help!

[swansont]

lets say you're converting 100km/s to miles.

 

 

[math]\frac {100km}{1sec} \cdot \frac {0.62 miles}{1km} = \frac {62 miles}{sec}[/math]

 

 

The important thing to note is that all of the terms after the original 100 km/sec are essentially multiplying by 1, which doesn't change the answer. You multiply by 0.62 mi/km because 1 km = 0.62 miles, so the ratio is the equivalent of 1. Same for the time conversion, or any other unit conversion you wish to do.

[CaptainPanic]

The important thing to note is that all of the terms after the original 100 km/sec are essentially multiplying by 1, which doesn't change the answer. You multiply by 0.62 mi/km because 1 km = 0.62 miles, so the ratio is the equivalent of 1. Same for the time conversion, or any other unit conversion you wish to do.

That sounds confusing (even to me, but I get it).

 

What swansont says is that unit conversion shouldn't change the actual speed you're doing... just the number and the unit.

 

If you were doing 100 km/hr (100 km/s = 360,000 km/hr, which is only for physics scientists, normal people do 100 km/h), then if you sit in your car, and you convert it to a different unit, it wouldn't feel any different, because it is not different.

 

p.s. I dislike any non-real-world calculations for educational purposes. If you can teach kids unit conversions, why not teach them a feeling for realistic everyday values for velocity too? So, if I were a teacher, I'd always use normal velocities that pedestrians, cars or airplanes can achieve. 100 km/s is high even for a spacecraft, but 100 km/h is a normal highway speed. Even the spacecraft Voyager 1 and 2 only reach about 17 km/s relative to the sun... but this is going off topic.

[burhan hafiz]

that also confuses me......... CaptainPanic

[alpha2cen]

To do unit conversion, first know basic physical conception.

And, practice to develop solving skill through solving many problems.

Real-world problem is good for understanding real-world.

But real-world problem is more complex than ideal problem.

We solve many ideal gas problem. Real gas problem is more complex.

But real gas problem is more useful to solve gas related problems in the field.