Please any one who knows physics well please help!

[Finns14]

Ok so I have home work due at 9am EST its now 4am and I need sleep and I can't seem to figure this problem out and I've been at it for hours.

A cab driver picks up a customer and delivers her 3.34 km away, driving a straight route. The driver accelerates to the speed limit and, upon reaching it, begins to decelerate immediately. The magnitude of the deceleration is 5.91 times the magnitude of the acceleration. Find the lengths of the (a) acceleration and (b) deceleration phases of the trip.

I still can't really figure it out and they gave me the tip


Hint

Let be the speed limit. Analyzing equation 2.9 () we see that for the first part of the motion the initial speed is zero and we have
.
For the second part of the motion, the final speed is zero and we have
.
Combine these two equations to eliminate . The relationship between and is known and can be used to eliminate in favor of . Finally, use the fact that the total distance, is known.

Which didn't really help me out either. Please help me out. Thanks

 

[Finns14]

Also bump if you feel my pain

 

[yhelothar]

Seems pretty easy to me, unless if I misunderstood the problem.

If the deceleration is 5.91 times the magnitude of the acceleration, that means the distance covered after it reached the max speed is 5.91 times shorter than when it was accelerating.

So then the deceleration phase travelled a total distance of 3.34/5.91 or 0.565km, and the acceleration travelled 3.34 - .565 or 2.77km

 

[NikPreviousAcct]

lol yeah solving that doesn't need a physics class... that can be solved in the algebra 1 class down the hall.

 

[Mardeth]

Originally posted by: virtualgames0
Seems pretty easy to me, unless if I misunderstood the problem.

If the deceleration is 5.91 times the magnitude of the acceleration, that means the distance covered after it reached the max speed is 5.91 times shorter than when it was accelerating.

So then the deceleration phase travelled a total distance of 3.34/5.91 or 0.565km, and the acceleration travelled 3.34 - .565 or 2.77km

Am I a total idiot or doesnt it go like this?

x = lenght of deceleration
5,91x = lenght of acceleration

x + 5,91x = 3340
6,91x = 3340 | /6,91
x = 483

Meaning that the car decelerated for ~483 meters and accelerated for ~2854 meters?

 

[yhelothar]

Yeah you're right.
I didn't put much thought into the problem