# Help with this subbing equation to another equation question

1. Sep 27, 2009

### kramer733

1. The problem statement, all variables and given/known data

runner A runs at 6.0 m/s for 10s. Runnber B accelerates from 4.0 m/s to 10.0 m/s. steadily. in 10s.
how far does runner a go?

2. Relevant equations

v2=v1+at
d=v1*t+0.5a*t^2
d=Vavg*t

3. The attempt at a solution
ok this is how much i've worked it out so far
but i'm stuck now
v2=v1+at
a=(v2-v1)/2
v1=6m/s
t=10s
d=v1*t+0.5at^2
d=6*10+0.5((v2-6)/10)*10^2
does 0.5 multiply the denominator?
am i even doing this right?

2. Sep 27, 2009

### Delphi51

d = vt = 6*10 = 60 m

3. Sep 27, 2009

### kramer733

so... >_> it was that simple.. >< But does the 0.5 multiply the denominator? Also is the 0.5 in this case the coefficient? Is that a coefficient?

4. Sep 27, 2009

### Delphi51

Hmm, too simple. Is there a part (b)? It might, for example, ask how far ahead one runner is after the 10 seconds.

5. Sep 27, 2009

### kramer733

Hm well part b was How far does runner B go? Found out it was 70

Now i'm stuck with this question. Do i start a new thread or do i post it here and just edit it?

6. Sep 27, 2009

### Delphi51

I agree with the 70.
Sorry about the delay; I had to lop two 6 inch branches off a tree 25 feet up!
Success, except I crashed one of them on my gate and damaged it.

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