Trouble calculating the acceleration

[ERAUin08]

Hey everyone I need some help with a problem. I am having trouble calculating the acceleration since I don't the the initial velocity.

Homework Statement

You are driving on the highway when you come across a speedometer test where the distances are maked on signs. When you pass the 0 mile marker, rather than holding your speed constant you press on the accelarator and hold it constant. You pass the 0.1 mile marker 16 s later, and the 0.2 mile marker 8 seconds after the 0.1 marker. a) What did you speedometer read at the 0.2 mile? b) what was your acceleration?

Homework Equations

d=v/t
d=0.2 miles=322m
time=24 s

The Attempt at a Solution

a) 322m=v/24s
V=13m/s
b) For the acceleration I am not sure.

Thank you for your help

 

[Dick]

If it's accelerating you CAN'T use v=d/t (and you can't use d=v/t anywhere. It's wrong). You have to use d=v0*t+(1/2)*a*t^2 where v0 is the initial velocity and a is the acceleration. Now if you put in the two given time points, you have two equations in the two unknowns v0 and a. Solve for them.