Question

A falling body has an initial velocity of 200cm/sec.How far will it drop before its velocity becomes 10,000cm/sec

Answer 1

The final velocity

$$v_f=v_i+gt$$

Hence

$$t=\frac{v_f-v_i}{g}=\frac{100\:\rm m/s-2\:\rm m/s}{9.8\:\rm m/s^2}=10\:\rm s$$