Question 2
What is the unit of acceleration?
The right answer is the one marked above.
m s-2. Acceleration is the change of velocity per second. Velocity is measured in m s-1, and that is divided by a time in seconds again:
m s-1 ÷ s = m s-2
m s-1 is the unit of velocity or speed; m is the unit of distance or displacement. Checking units is the quickest way to test whether an answer can be right.