Two balls are dropped from the same height at  1 second interval of time. The separation between the two balls after 3 seconds of the drop of the 1st ball is…….g=9.8 m/s2

For the motion of the 1st ball u=0 ; a=g ; t1=3 s∴ The distance travelled by the 1st ball in 3sec  s1=12gt12 =12g9=92g...........(i) For the motion of 2 ball u=0 ; a=g ; t2=3 −1 =2 s The distance travelled by the 2ball in 2s s2=12gt22 =12g22=2g.........(2) Separation between the two balls  =s1-s2=92g−2g=52g=52×9.8=24.5m