Question

If you speed up from rest to 12m/s in 3 seconds, what is your acceleration?

Answer 1

The answer id 4 m/s/s this is because 12/3 = 4 and an easy way to get the units is put the two together

Acceleration = m/s (Meters per second)
Time = s (Seconds)

m/s/s = Meters per second/ Per second

Answer 2

b) 4m/s/s

This is because you divide the speed you reach, by the time it takes to get to that speed:

12m/s ÷ 3s = 4m/s/s

The units come from what you divide, meters per second ÷ seconds this can be written as m/s/s or ms-²