Question

A car slams on its brakes creating an acceleration of -3.2 m/s². It comes to rest after traveling a distance of 210 m. What was its velocity before it began to accelerate?

Answer 1

Answer: 36.66m/s

Explanation:

Listing everything is gives you:

Vf = 0

a = -3.2

Δx = 210

Vi = ?

Pick one of the kinematic equations to find the missing variable

I used this one: $Vf^2=Vi^2 + 2a$Δx

When you plug everything in, you get

0 = $Vi^2 -1344$

add 1344 to both sides and square root to get Vi = 36.66