Question

Felipe drives his car at a velocity of 28 m/s. He applies the brake, which slows the vehicle down at a rate of 6. 4 m/s2 and causes it to slow to a stop. How long does it take for the car to stop? Round your answer to the nearest tenth.

Answer 1

Hi there!

We can use the kinematic equation:

$v_f = v_i + at$

vf = final velocity (0 m/s, breaking to a stop)

vi = initial velocity (28 m/s)

a = acceleration (-6.4 m/s², breaking)

time (sec)

Plug in the given values and solve.

$0 = 28 - 6.4t\\\\-28 = 6.4t\\\\\large\boxed{t = 4.375 s}$