Which has the greater acceleration, a car that increases its speed from 50 to 62 km/h, or a bike that goes from 0 to 12 km/h in the same time?

Answer 1

a1 = (v-Vo)/t = (62-50)/t = 12/t.
a2 = (0-12) = -12/t.

Since their times and change in speed
are equal, the magnitude of their acceleration are equal. The neg. sign
means the bike was stopping or slowing
down.

Answer 2

The accelerations are the same.