Problem Solving

[learner27]

Hey guys Im just here to ask if my answer is correct, if not please help me because im trying to get ready for our exam tomorrow , so here it is:

 

Five students went on a trip to the North of California. They traveled at an average of 40km/hr in 3 hrs before taking a snack at Mcdonalds. On the second leg of the trip , they traveled at an average of 20m/s in 2hrs. before taking a coffee break at Starbucks. Then they finally traveles at an average of 60 ft/s in 1 1/2 hours before reaching theyre final destination.What was the total distance they covered in MILES?

 

here is my answer

 

S= 53.885 miles

 

* i used the V= Vi +Vf/2

and S=vt

 

 

thanks guys

[CaptainPanic]

Eeh... that's not correct.

 

First you must decide in which unit you will add up all the things (note: it can be miles, but not necessarily).

 

Then you convert kilometers to miles.

40 km = ?? miles --> 40 km/hr = ?? mph

... and in 3 hrs, they therefore did 3*?? miles.

 

Then you convert meters into miles.

20 m = ?? miles

But this time, it's in meters per second, so you have to multiply by the number of seconds (how many seconds in 1 hour?).

 

Etc, etc.

 

And finally, you just add up the 1st, 2nd and 3rd leg of the journey.

[learner27]

I have a question thats what im trying to discover how to convert

KM/h to miles/seconds

 

i dont know how to convert two units at the same time...

[CaptainPanic]

i dont know how to convert two units at the same time...

Then don't.

 

Do it one at a time.

[learner27]

HOw Sir?

first on 40km/h

i converted 40 km to miles and i got 24.84 miles

then 20 meters to miles = .01

then 60 ft to miles = .01

 

i dont know what to do with the time.. ?

[CaptainPanic]

HOw Sir?

first on 40km/h

i converted 40 km to miles and i got 24.84 miles

then 20 meters to miles = .01

then 60 ft to miles = .01

 

i dont know what to do with the time.. ?

How many seconds are in an hour?

 

Btw, you probably want one or two more decimals in your conversions from ft and meters to miles.

[learner27]

3600 seconds sir

and on ft..

.011 sir...

Edited July 24, 2012 by learner27

[CaptainPanic]

3600 seconds sir

and on ft..

.011 sir...

If I travel 1 meter in 1 second, then how many meters did I travel in 1 hour?

[learner27]

3600 meters??

sir can u teach me how to convert units like that compound units im afraid that it will come out on our exam tomorrow i want to get high grade please teach me

[CaptainPanic]

3600 meters??

Correct. So, now you actually already have converted the time units, but from seconds to hours. You just didn't know you can do it already.

 

If I write that I walk 1 meter in 1 second, that's the same as saying I do 1 m/s.

 

So, if I ask you how many meters I then did in 1 hour, then I ask you to go from m/s to m/hr, and you did that without mistake.

 

So, to go from ft/s to miles/hr, you do it in 2 steps: first from ft/s to ft/hr, and then to miles/hr, or the other option is first from ft/s to miles/s and then to miles/hr.

 

I've seen you do both steps correctly already, so I think my work is done here.

[learner27]

sir is this conversion now right?

40 km to miles and i got 24.84 miles/sec

then 20 meters to miles = .01miles/sec

then 60 ft to miles = .011miles/sec

 

Edited July 24, 2012 by learner27