[1] As acceleration, the unit is interpreted physically as change in velocity or speed per time interval, i.e. metre per second per second and is treated as a vector quantity.
The average acceleration a can be calculated by dividing the speed v (m/s) by the time t (s), so the average acceleration in the first example would be calculated:
Newton's second law states that force equals mass multiplied by acceleration.
One newton equals one kilogram metre per second squared.
Therefore, the unit metre per second squared is equivalent to newton per kilogram, N·kg−1, or N/kg.
[2] Thus, the Earth's gravitational field (near ground level) can be quoted as 9.8 metres per second squared, or the equivalent 9.8 N/kg.
This is for compatibility with East Asian encodings and not intended to be used in new documents.