The length of a rod is exactly 1m when measured at rest.
Question:

The length of a rod is exactly $1 \mathrm{~m}$ when measured at rest. What will be its length when it moves at a speed of

(a) $3 \times 10^{5} \mathrm{~m} / \mathrm{s}$,

(b) $3 \times 10^{6} \mathrm{~m} / \mathrm{s}$ and

(c) $3 \times 10^{7} \mathrm{~m} / \mathrm{s}$ ?

Solution: