Question

Two bodies begin to fall freely from the same height but 2nd one falls T seconds ater 1st.The time(after which the 1st body begin to fall) when the diatance between them is L is:
Options
1.T/2 2.T/2+L/gT 3.L/gT 4.T+2L/gT


I am not understanding how to find the time and what is the significance of L how to use ut!??

Answer 1

The problem is really worded poorly. It is asking if two objects are dropped at slightly different times, how does the length between them vary with time.

distancefirst=1/2 g t^2
distancesecond=1/2 g(t-T)^2
distance L= distancefirst-distancesecond
= 1/2 g (t^2-(t-T)^2)=L
so solve for t.

1/2 g (t^2-t^2+2tT-T^2)=L
1/2 g T(2t-T)=L
well, you can solve for time t.