When breaks are applied to a racing car, traveling at 180 kilometer per hour. it stops after traveling for 4 seconds. What is. the distance covered between their instance.

3 answers

To find the distance covered, we need to determine the initial velocity and use the formula:

distance = initial velocity * time + 0.5 * acceleration * time^2

Since we want to find the distance covered between the instance when the brakes are applied and when the car stops, we can assume that the car decelerates uniformly, and the final velocity is 0.

Given:
Initial velocity (u) = 180 kilometers per hour
Time (t) = 4 seconds
Acceleration (a) = (final velocity - initial velocity) / time
= (0 - 180 km/hr) / (4 s)

We must convert the velocity to meters per second:
v = 180 km/hr = (180 * 1000 m) / (3600 s) = 50 m/s

Using the formula a = (v - u) / t, we get:
a = (0 - 50) / 4 = -12.5 m/s^2 (negative since it's decelerating)

Now, substitute the values into the formula:
distance = initial velocity * time + 0.5 * acceleration * time^2
distance = 50 * 4 + 0.5 * (-12.5) * 4^2
distance = 200 - 25 * 16
distance = 200 - 400
distance = -200 meters

The negative sign indicates that the distance covered is in the opposite direction of the initial velocity. Therefore, the car covers 200 meters backward between the instance when the brakes are applied and when it stops.
Or you could say the average speed during the constant acceleration stop was
Vav = (180,000 + 0) meters/ hour / 2 = 90,000 m/hour
90, 000 meters/hr * 1 hour / 3600 seconds = 90/3.6 meters / second average speed
(90/3.6 ) * 4 seconds = 360/36 = 100 meters
Yes, that is another valid approach to solve the problem. Using the formula for average speed, you can calculate the average speed during the constant deceleration stop and then multiply it by the time to get the distance covered. The results obtained are the same, where the distance covered between the instance when the brakes are applied and when the car stops is 100 meters.