Question 1001158
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2. A stone is dropped from the top of the building 20m high. A second stone is dropped from half-way up the same building. Find the time that should elapse between the release of the two stones if they are to reach the ground at the same time.
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The dropped stones have zero initial velocity.


So,  h= {{{(g*t^2)/2}}},  where  g  is free fall acceleration  9.81 {{{m/s^2}}},  t  is time in seconds and  h  is the traveled distance  (the height)  by the falling body.


Thus we have two equations for two falling bodies:


20 = {{{(9.81*t[1]^2)/2}}} 


and


10 = {{{(9.81*t[2]^2)/2}}}.


Find  {{{t[1]}}}  and  {{{t[2]}}}  from these equations.


Then  {{{t[1]}}} - {{{t[2]}}}  would be your answer.