Water drops are falling from a pipe at 5 m height at regular interval of time. When the third drop is released at the same time the first drop touches the ground. Then the height of second drop from ground is ....... m. (g = 10 `ms^(-2)`)

Options

A. `1.25`
B. `3.75`
C. `2.50`
D. `4.0`

Answer

B

Explanation

Height of pipe h = 5 m
Time taken by `1^(st)` drop to reach at ground is .t. then,
`d = v _(0) t + 1/2 at ^(2)`
`5=0 + 1/2 xx (10) xx t ^(2)`
`therefore t ^(2) =1 implies t =1 s`
Thus at 1 sec time `1^(st)` drop reaches ground and `3 ^(rd)` drop is released.
Thus, time taken by `2^(nd)` drop,
`d =0 xx t +1/2 xx 10 xx (0.5) ^(2)`
`d = 1.25 m`
Thus, height of drop from ground `=5-1.25 m = 3.75 m`