two diamond begin a free fall from rest from the same height,1.0s apart. how long ater the first diamond begins to fall will the two diamonds be 10m apart.

consider situation after 1s

dist. travelled by first dimond is 5m(g=10); velocity is 10 m/s

at this point another dimond is.dropped from same height.... now consider relative motion b/w both of them

the first dimond is moving with 0 acceleration and 10m/s speed with respect to the second.. whereas the second one can be cosidered at rest @ the same height...

thus after 0.5 second the first dimond moves  5m   with respect to the second one.... thus on adding it with initial gap of 5m we get 10 m....

thus after 1.5 seconds of fall of the first dimond both the dimonds will be seperated by 10m 

the answer is 2.732