How do you convert m/s^2 to km/h?

1. Sep 22, 2004

Kdawg

How do you convert m/s^2 to km/h?

2. Sep 22, 2004

plover

At least in the form you asked the question, you can't. m/s2 is a unit for acceleration while km/h is a unit for speed.

3. Sep 22, 2004

KaneOris

well you can if you have the delat t of a

4. Sep 22, 2004

KaneOris

But if you are trying to convert ms^-1 than its rather easy, theres a couple ways of doing it.
I do it like such
((36km/60)/60)*1000
which is equal to 10ms^-1

Theres some really easy way to do it, but this one never fails and it doesnt take that much longer so i just use this one.

5. Sep 22, 2004

Kdawg

Oh, that would make sence wouldnt it, lol. Im trying to figure out this problem.
A bus traveling at +29 km/h accelerates at a constant +3.7 m/s2 for 6.3 s. What is its final velocity in km/h?
This is my work so far, what am I doing wrong.
Vi = 29Km/h
a = 3.7m/s^2
t = 6.3s
Vf = ?

Vf = Vi + at
Vf = 29 + 3.7 * 6.3
Vf = 52 - With right sig figs

6. Sep 22, 2004

plover

Looks good to me.

7. Sep 22, 2004

Kdawg

Thats what I thought but the damn webassign keeps marking it wrong.

8. Sep 22, 2004

KaneOris

I can see why from here,
Vf = Vi +at
SI UNITS!
Velocity SI unit is ms^-1
Therefore 29kmh^-1
Needs to be converted to ms^-1

9. Sep 22, 2004

KaneOris

What is its final velocity in km/h?
And then convert it back

10. Sep 22, 2004

KaneOris

You have to remember to convert stuff, i will never forget, i lost 15 marks out of 50 on my last exam from not converting to the SI units

11. Sep 22, 2004

Kdawg

I converted 29km/h to 8.0556m/s the multiplied 8.0556 + 3.7 * 6.3 = 30.6256
then converted that to 110. That obviously isnt right, what am I doing wrong.

12. Sep 22, 2004

plover

Bleah. Of course. I wasn't looking at the units.

13. Sep 22, 2004

KaneOris

Seems right to me... Remember, think of how long 6.3 seconds is when your accelerating in a car. Like when you go onto a freeway, you would really only accelerate for about 3 seconds to get to 100km, from about 50..., so 6 seconds is actually a long time to accelerate for

14. Sep 23, 2004

tyco05

Try evaluating this again I don't seem to get the same answer for 8.05556+(3.7*6.3) as you do.

(and hence the converted figure is different as well)

15. Sep 23, 2004

tyco05

This really depends on how hard you put your foot on the accelerator (or how good your car is!)

16. Sep 23, 2004

KaneOris

Yes, but you know what i mean, 6.3 seconds is a long time to accelerate, although the sound of it isnt very much, its a pain in the A if you look at your watch and wait for 6 or 7 seconds to pass...