If a car slows from 15 m/s to 5 m/s over 5 seconds, what was the car's acceleration?

-2 ms⁻²

Explanation:

Here,

Initial velocity (u) = 15 ms⁻¹

Final velocity (v) = 5 ms⁻¹

Time (t) = 5 seconds

Acceleration (a) = ?

Formula:

a = (v-u) / t

⇒ a = (5-15) / 5

⇒ a = - 10/5

⇒a = - 2

∴acceleration of the the car was - 2 ms⁻²

Note:

The answer is negative because of decreasing the velocity. That means it is deceleration.