Question

A car came to rest when

(a). brake was applied for 8s to get a retardation of 6 m/s calculate how far the car would have travelled after applying the brake.

(b). If the velocity of a car moving with uniform velocity changes from do m/s to 40 m/s in 55. Find acceleration of the car.​

Answer 1

(a)

$acceleration = -6 \:m/s^{2} \\time = 8 s\\final velocity = 0\\\\v=u+at\\=>0=u-6*8\\=> u = 48 m/s\\\\s = ut + \frac{1}{2} at^{2} \\=> s = 48*8\: -\frac{1}{2} *6*8^{2}\\=>s = 384-192\\=> s = 192 m \\\\Hence \: the \: distance \: travelled \: by \: the \: car \: is \: 192\:m$

Please write the initial velocity in bit (b)

Hope it helps