Two bodies begin to fall freely from the same height. The second body begins to fall `'tau'` s after the first. After what time from the beginning of first body dose the distance between the bodies equals to l?

Explanation

Let the time of fall of the 1st body be t seconds Time of fall of second body `=t-tau`
Distances of free fall of the bodies in the above time intervals respectively are
`H_(1)=(gt^(2))/(2), H_(2)=(g(t-tau)^(2))/(2)`
`H_(1)=(gt^(2))/(2), H_(2)=(g(t-tai)^(2))/(2)`
Therefore `l=H_(i)-H_(2)=gt tau-1/2 gt^(2)" "therefore t=l/(g tau)+tau /2`