Question

CGS unit of speed is
A. cm/sec
B. km/hr
C. km/sec
D. m/sec

Answer 1

Hint: Learn the definition of speed and then find its unit. After this learn the meaning of CGS then find the unit of speed in CGS. Convert MKS unit into CGS.

Complete step by step answer:
What is a CGS unit?
CGS – centimeter-gram-second
Base units and their CGS units are as follows-

Speed is the distance traveled per unit of time. It is how fast an object is moving. Speed is the scalar quantity that is the magnitude of the velocity vector. Speed has no direction because scalar quantity has only magnitude not any direction. If speed is higher that means an object is moving faster.
$S=\dfrac{d}{t}$
In CGS unit
$\begin{align}
  & S=\dfrac{cm}{s} \\
 & Speed=cm{{s}^{-1}} \\
\end{align}$
Hence option A is correct

Additional Information:
Seven base units and their SI units are as follows-

Note: Students always make mistakes in unit conversion. They write MKS units instead of CGS units or vice versa. So they get the wrong answer.
The MKS unit of speed is as follows-
$\begin{align}
  & S=\dfrac{m}{s} \\
 & Speed=m{{s}^{-1}} \\
\end{align}$