Question

I have the equation 'change in distance = 1/2 x (vf+vi) x change in time (or delta t)' for uniform acceleration. However, I am totally lost when it comes to rearranging it. I need to rearrange it for inital speed (vi) and change in time (delta t). Can someone please help?

Answer 1

That equation is a pretty basic one, it does hold true for uniform acceleration. Basically, the equation is

distance= average speed *time
where of course average speed is the average of starting and finishing speeds.

average speed= 1/2 (Vf+Vi)*time

If you want Vi, mulitiply both sides by 2, then divide both sides by time, finally, subtract Vf from both sides. This is basic algebra.

d=1/2 (vf+Vi)t
2d=(Vf+Vi)t
2d/t= Vf + Vi

2d/t -Vf= Vi

I will be happy to critique your rearrangement to solve for time.

If your algebra is this weak, you may want to consider getting a tutor on that. Discuss it with your teacher and parents.

Answer 2

In order to get the time, would I have to do the vf-vi divided by 2, times the distance??

I guess I really do need a brush-up on algebra!

Answer 3

**Oops, I meant vf+vi.

Is that the right equation?