Question

On a quarter-mile drag strip, 402 meters, a car has a racing acceleration of +15.0 m/s² and a braking acceleration of -13.0m/s².

9: What is the distance the car moves until coming to a stop after crossing the finish line:

______________ meters _______________feet

Answer 1

To find the distance after which the car will stop after the finish line, we have to first calculate the speed at the finish line, and then from that using the value of the braking acceleration, we will obtain the distance covered before stopping.

So, distance (s) = 402 m

initial speed (u) = 0 m/s

Acceleration (a) = 15 m/s2

final speed, (v) = ?

We will use the kinematic expression

So,

Hence, final speed v = 109.82 m/s

Now that we have obtained the speed at the finish line we will use this informataion to find how far the car goes before stopping.

For this case, initial velocity (u') = 109.82 m/s

final velocity (v') = 0 m/s

acceleration (a') = -13 m/s2

Distance (s') = ?

We will again use,

So,

Hence, s' = 463.85 m = 1521.82 ft

So, after crossing the finish line the car before stopping moves a distance of 463.85 meters or 1521.82 feet