motion, constant acceleration

alexgraham

A car slows down from 23 m/s to rest in a distance of 85m. what was its acceleration, assumed constant?



a=Δv/Δt x=1/2at^2



i don't know where to start

Dickfore

what is the velocity-displacement formula?

alexgraham

v^2=2ax

alexgraham

in that equation is v the change in velocity?

Reptillian

Ignore this post, it was bad advice!

alexgraham

v^2=2ax

alexgraham

okay thanks i guess my teacher messed up

Reptillian

I'm sorry, I just gave you some bad advice...ignore my first response.

Reptillian

I don't know what I was thinking, but yeah you use (final velocity)^2 = (initial velocity)^2 + 2*a*x and just substitute the stuff you know and solve for a.

Ratch

Does anyone know how to derive V^2=V0^2+2as

Ratch

Dickfore

Take the velocity-time equation:
[tex]
v = v_{0} + a \, t
[/tex]
and the position time equation:
[tex]
x = v_{0} \, t + \frac{1}{2} \, a \, t^{2}
[/tex]
and eliminate time t.

azizlwl

Work energy theorem
KE_v2-KE_v0=mas