What are the steps to solving a velocity-time problem with uniform acceleration?

[200krisx]

Homework Statement

A motorist starting a car from rest accelerates uniformly to a speed of V ms in 6 seconds. He maintains this speed for 50 seconds and then applies the brake sand decelerates uniformly to rest. His deceleration numerically equal to four times the initial acceleration. The total distance traveled is 1000 meters

Homework Equations

1) Sketch a vt graph for the journey
2) calculate the time during which the deceleration takes place
3) calculate value of v
4) Calculate the initial acceleration.

The Attempt at a Solution

1) is straight forward
2) a= 6/4 =1.5s
3) can you use s= ut+ 1/2at^2?
4) .?

I struggle with these types of question so any help would be greatly appreciated,

Thanks,

 

[lewando]

2) Agree.
3) That is good one to use, but I think it might be easier to solve 4), a, first.
4) Break the problem up into 3 time/distance zones. Looking at zone 1 (0<t<6) first, what would you get for v (at the 6-second point) in terms of a? What would you get for the distance traveled in zone 1, in terms of a, etc...