how long will it take for a car to accelerate to come to a stop if it is traveling at 20 m/s and the car has a maximum deceleration of 6 m/s squared?

Question

So far I think im supposed to do

6-20/26

Answer 1

Think of the units:

(20 m/s) / (6 m/s^2) = 3.33 s

Think of it like this. Every second the speed decreases by 6 m/s. So, it takes 3.33 seconds to lose all 20 m/s.

Or, how about this:

a = ∆v/∆t
so, ∆t = ∆v/a = (0-20)/-6 = = 3.33