A car slows down from 24 m/s to rest in a distance of 90 m. what was its acceleration, assumed constant? incorrect: your answer is incorrect. m/s2

The initial speed of the car is

V₁ = 24 m/s

Because the car comes to rest, the final speed of the car is

V₂ = 0

The distance traveled while coming to rest is

d = 90 m.

Let a = the constant acceleration.

Use the formula

V₂² = V₁² + 2ad

That is,

0 = (24 m/s) ² + 2 * (a m/s²) * (90 m)

Obtain

180a = - 576

a = - 3.4 m/s²

Because the answer is negative, the car decelerates.

Answer:

The acceleration is - 3.2 m/s² (or a deceleration of 3.2 m/s²).