Ask Questions, Get Answers

Want to ask us a question? Click here
Browse Questions
Home  >>  JEEMAIN and AIPMT  >>  Physics  >>  Class11  >>  Motion in a Straight Line
0 votes

Drops are falling at regular intervals of time from the roof of a building 16 m high. If the first drop reaches the ground at the instant the fifth drop start falling, find the heights of the various drops at the instant the first drop reaches the ground ?

Can you answer this question?

1 Answer

0 votes
Let the drops fall at a regular interval of time t.
When the fifth drop starts falling, the time elapsed will be $t,2t,3t$ and $4t$ for the fourth , third, second and first drop respectively and if the distances covered are $S_4,S_3,S_2,S_1$ then
$S_1= \large\frac{1}{2}$$g(4t)^2=16 \times \large\frac{1}{2}$$gt^2$
$S_2= \large\frac{1}{2}$$g(3t)^2=9 \times \large\frac{1}{2}$$gt^2$
$S_3= \large\frac{1}{2}$$g(2t)^2=4 \times \large\frac{1}{2}$$gt^2$
$S_4= \large\frac{1}{2}$$g(t)^2= \large\frac{1}{2}$$gt^2$
Here $S_1= 16 m$ Therefore $\large\frac{1}{2}$$gt^2=1m$
Hence $S_2= 9 m,S_3= 4 m$ and $S_1 =1m$ .
The height of the various drops from the surface of the earth will be $0,7,12,15\;and \;16 m$
answered Jul 25, 2014 by meena.p

Related questions

Ask Question
student study plans
JEE MAIN, CBSE, NEET Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App