Question

While traveling north on an expressway, a car traveling 60 mph (miles per hour) slows down to 30 mph in 12 minutes due to traffic conditions

Answer 1

acceleration = - 150 m/s^2

distance = 9 miles.

Step-by-step explanation:

initial speed, u = 60 mph

time, t = 12minutes = 0.2 hour

final speed, v = 30 mph

Let the acceleration is a and the distance is s.

By the first equation of motion

v = u + at

30 = 60 + a x 0.2

a = - 150 m/s^2

Let the distance is s.

Use third equation of motion is

`v^2 = u^2 + 2 a s \\\\30^2 = 60^2 + 2 * 150* s\\\\s = 9 miles`