# Two diamonds begin a free fall from rest from same height $1.0 \; sec$ apart How long after will the two diamonds be 10 m apart ? $(g=10 m/s)$

$(a)\;2\;sec \quad (b)\;1.5 \;sec \quad (c)\;1\;sec \quad(d)\;2.5 \;sec$

We have
$S_1(t)-S_2(t-1)=10$
$\large\frac{1}{2}$$\times gt^2-\large\frac{1}{2}$$ g(t-1)^2=10$
$t=1.5 \;sec$
Hence b is the correct answer.

edited Jan 26, 2014 by meena.p