Derivation of the Kinematic Equations

[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:
$$v = v_{0} + a \, t$$
and the position time equation:
$$x = v_{0} \, t + \frac{1}{2} \, a \, t^{2}$$
and eliminate time t.

 

[azizlwl]

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

Ratch

Work energy theorem
KE_v2-KE_v0=mas