Are there any basic formulas for motion in kinematics?

[patrickking]

I have no idea if this is the right forum but I am doing the kinematics chapter in 2204 and I was wondering if anyone had the bassic forumlas for motion.

 

[Retsam]

Yea, try :

V = u+at

(V^2) = (u^2) + 2as

s = ut + 0.5a(t^2)

Where,

u = initial velocity
v = final velocity
s = distance (or more correctly displacement)
a = acceleration
t = time

 

[patrickking]

In my corse we use V1 and V2, D is Displacement, Is this like V1= U, V2=V and D=S?

 

[patrickking]

The given information to the simple problem I am trying to complete is V1=10, A=1, V2= 15 and D=?. I just lost my formula sheet and I am lost.

 

[Retsam]

Yea its same thing as you've put there, and as for the first question you would use,

(v2^2) = (v1^2)+2ad

and rearrange for d

 

[patrickking]

So to rearrange for D would you use D= (V1^2) + 2a over (V2^2)? I used that and ended up with 0.4 for my answer, I don't believe that's correct?

 

[patrickking]

This is all in Meters per second also.

 

[Retsam]

Nope that's wrong, rearrange it in these steps :

(v2^2) = (v1^2)+2ad

You want to clear everything off the right hand side to leave d on its own, so start by moving (v1^2) :

(v2^2) - (v1^2) =2ad

And now divide both sides by 2a, and so :

(v2^2) -(v1^2) = 2ad

((v2^2) -(v1^2))/2a = 2ad/2a

to get :

((v2^2) -(v1^2))/2a = d

As you can see the 2a on the right hand side cancels when you divide that side by 2a

And yea everythign is in SI units so that's meters per second, meters, seconds etc

 

[patrickking]

OK I did that and came out with 125 m/s which I think looks like it may be correct. But I'm not sure.

 

[Retsam]

Not quite, you only divided by a, when its supposed to be divide by 2*a
And d is a distance so its measured in just m, m/s is for velocity