Question

Solve this:

3. Drops of water fall at regular intervals from roof of a building of height H = 16 m, the first drop striking the ground at the same moment as the fifth drop detaches itself from the roof . The distances between separate drops in air as the first drop reaches the ground are:

(A) 1m, 5m, 7m, 3m (B) 1m, 3m, 5m, 7m
(C) 1m, 3m, 7m, 5m (D) None of the above

Answer 1

Dear Student,


$$\begin{gathered} letthetimeintervalbetbetweenthefallofdrop. \\ timetakenby1stdroptoreachthegroundis4t \\ 4t=\sqrt{\frac{2*16}{g}} \\ t=0.45sec. \\ positionofseconddrop=16-\frac{10*{\left(3t\right)}^2}{2}\approx 7mfromthreground. \\ positionofthethirddropfromtheseconddrop=9-\frac{10*{\left(2t\right)}^2}{2}\approx 5m \\ positionofthefourthdropfromthethirddrop=4-\frac{10*{\left(t\right)}^2}{2}\approx 3m \\ positionoffifthdropfromthefourthis1m \\ 1,3,5,7 \\ optionB \\ Regards \end{gathered}$$