A car accelerates uniformly from rest for a time of 12 sec. The rate of acceleration is 4m/s^2. What is the velocity at the. end of 12 sec?

initial velocity = 0 = v ₍i₎

final velocity = ? = v ₍f₎

t = 12 sec

Acceleration = 4m/s²

First we have to find the distance d, for this we use the formula,

D = v ₍i₎t + 1/2at²

D = 0 (12) + ½ (4) (12) ²

Distance = d = 288 m

Now to find the Vf use the formula,

V ₍f₎² = v ₍i₎² + 2ad

V ₍f₎² = (0) 2 + 2 (4) (288)

V ₍f₎² = 2304

V ₍f₎ = 48 m/s

so the velocity at the end of 12 sec is 48 m/s