Question

A driver of an automobile travelling at a constant speed of 20m/s suddenly applies a brake and the automobile comes to rest in 2 seconds after skidding for a certain distance. What is the length of the skid distance? A. 400m B. 20m C. 40m D. 10m.​

Answer 1

20 meters

Step-by-step explanation:

d = (1/2) * a * t^2

where:

d is the distance (skid distance),

a is the acceleration,

t is the time.

In this case, the automobile comes to rest, so the final velocity is 0 m/s. We know the initial velocity is 20 m/s, and the time is 2 seconds.

To find the acceleration, we can use the formula:

a = (final velocity - initial velocity) / time

a = (0 - 20) / 2 = -20 / 2 = -10 m/s^2

Substituting the values into the equation of motion:

d = (1/2) * (-10) * (2^2)

d = (1/2) * (-10) * 4

d = -20 meters

The length of the skid distance is 20 meters (option B).