What is the SI unit of speed ?
$
  (a){\text{ m/s}} \\
  (b){\text{ cm/s}} \\
  (c){\text{ m/}}{{\text{s}}^2} \\
  (d){\text{ cm/}}{{\text{s}}^2} \\
$

Hint – In this question use the concept that SI unit of distance is meter and the SI unit of time is second. Use the relation between speed distance and time, figure out the SI unit.

Complete step-by-step answer:
As we know that the speed is the ratio of distance to time.
Therefore, speed = (distance/time).
Now as we know that the S.I unit of distance is meter (m).
And we know that the S.I unit of time is second (s).
Therefore, the S.I unit of the speed is (meter/second)
S.I unit of speed = (m/s).
So this is the required answer.
Hence option (a) is correct

Note – SI units is known as international systems of units, it is a system of physical units based upon the meter, kilogram, second, ampere, kelvin, candela and mole together with a set of prefixes to indicate the multiplication or division by a power of 10.