Motion in one dimension problem

[vv_ramirez259]

Homework Statement

An unmarked police car traveling a constant 85 is passed by a speeder. Precisely 1.00 after the speeder passes, the police officer steps on the accelerator. If the police car accelerates uniformly at 3.00 and overtakes the speeder after accelerating for 5.00 , what was the speeder's speed?

Homework Equations

vf = vo + at
avg velocity = (vf + vo) /2
d = vo)t + (1/2) at2
vf2 = vo2 + 2ad

The Attempt at a Solution

I found that t=1s, a= 23.6 m/s2.. I am unsure what formula to use

 

[Andrew Mason]

Homework Statement

An unmarked police car traveling a constant 85 is passed by a speeder. Precisely 1.00 after the speeder passes, the police officer steps on the accelerator. If the police car accelerates uniformly at 3.00 and overtakes the speeder after accelerating for 5.00 , what was the speeder's speed?

Homework Equations

vf = vo + at
avg velocity = (vf + vo) /2
d = vo)t + (1/2) at2
vf2 = vo2 + 2ad

The Attempt at a Solution

I found that t=1s, a= 23.6 m/s2.. I am unsure what formula to use

Draw a distance time graph for the police car. Let the time the speeder passes the police car be the origin. At t=6, what is d?

Now you can draw the graph for the speeder. What two points do you have for the speeder's graph? What kind of graph is it? What physical quantity does the slope relate to?

BTW, what units of distance are you using? 85 m/sec is about 200 mph.

AM