[western50]

Two cars start from rest at a red stop light. When the light turns green, both cars accelerate forward. The blue car accelerates uniformly at a rate of 3.2 m/s2 for 4.2 seconds. It then continues at a constant speed for 10.2 seconds, before applying the brakes such that the car's speed decreases uniformly coming to rest 203 meters from where it started. The yellow car accelerates uniformly for the entire distance, finally catching the blue car just as the blue car comes to a stop.

1. How fast is the blue car going 1.7 seconds after it starts?

2. What is the acceleration of the yellow car?

In what ways I can start this problem?

[Unknown008]

By taking bit by bit.

Use the equation

v = u + at

to find the speed of the blue car at 1.7 s

2. Find the distance travelled by the blue car during the acceleration part, the uniform motion part and the braking part. From this, deduce the time the car takes to come to rest from it's maximum speed.

Equations you might want to use:

s = ut + 0.5at^2
2s = (u + v)t

Then, using the time and the distance, find the acceleration of the yellow car.

s = ut + 0.5at^2