At highway speeds, a particular automobile is capable of an acceleration of about 1.6 m/s2. At this rate, how long does it take to accelerate from 81 km/h to 117 km/h?

Answer 1

Vo = 81000m/h * (1/3600)h/s = 22.5m/s.

Vf = 117000m/h * (1/3600)h/s = 32.5m/s.

Vf = Vo + at,
t = (Vf-Vo) / a
t = (32.5 - 22.5)/ 1.6 = 6.25s.