$A$ piece of length $3.532 \ m$ is cut from a rod of length $43.4 \ m$. The length of the remaining rod in metre is (up to correct significant figures)

Which of the following measurements of length is the most precise? Why?
$(i) \ 2.0 \ cm$
$(ii) \ 2.00 \ cm$
$(iii) \ 2.000 \ cm$

The number of significant figures in $3.78 \times 10^{22} \ kg$ is

Write the rules for rounding off numbers.

An object of mass $m = 3.513 \ kg$ moves along the $x$-axis with a velocity of $5.00 \ ms^{-1}$. The magnitude of its momentum can be recorded as $...... \ kg \ ms^{-1}$.

$A$ student measuring the diameter of a pencil of circular cross-section with the help of a vernier scale records the following four readings: $5.50\, mm, 5.55\, mm, 5.45\, mm, 5.65\, mm$. The average of these four readings is $5.5375\, mm$ and the standard deviation of the data is $0.07395\, mm$. The average diameter of the pencil should therefore be recorded as: