A ball rleased from the tope of a tower travels ` (11) /( 36) ` of the height of the tower in the last second of its journey. The height of the tower is (g= 10 ms^(2)).

Options

A. 11 m
B. 36 m
C. 47 m
D. 180 m

Answer

D

Explanation

`(11h)/36 = 10/2 (2n-1)`
`11/36 xx 1/2 xx 10 n^(2) = 10 /2 (2n -1) "or " 2n -1 = 11/36 n^(2)`
or `11n^(2) =72 n - 36n " or " 11n^(2) - 72 n + 36 = 0`
or ` 11n^(2) - 66n - 6n + 36 = 0 `
or `11n (n -6) -6 (n-6) = 0 " or " (11n -6) (n-6)=0`
or n = 6 `" "` [Rejecting fractional value]
` :. h = 1/2 xx 10 xx 6 xx 6 m = 180 m`