Precise measurements of physical quantities are a need of science. For example,to ascertain the speed of an aircraft,one must have an accurate method to find its positions at closely separated instants of time. This was the actual motivation behind the discovery of radar in World War $II$. Think of different examples in modern science where precise measurements of length,time,mass,etc.,are needed. Also,wherever you can,give a quantitative idea of the precision needed.

(N/A) Precise measurements are fundamental to scientific progress. Here are some examples:
$1$. Time: In atomic clocks,precision is required to the order of $10^{-13} \; s$ for $GPS$ synchronization.
$2$. Length: In $X$-ray crystallography,inter-atomic distances are measured with a precision of about $10^{-10} \; m$ ($\mathring{A}$ scale).
$3$. Mass: Mass spectrometers allow for the measurement of atomic masses with a precision of $1$ part in $10^6$ or better.
$4$. Ultra-fast processes: Laser pulses can measure time intervals as short as $10^{-15} \; s$ (femtoseconds) to study chemical reactions.