A) 44.1 m and 3s
B) 44.1m and 5s
C) 4.41 m and 3s
D) none of the above
Correct Answer: A
Solution :
If the height of the tower is \[h\]metre and the total time of fall is n seconds, then \[\frac{5}{9}h=0+\frac{9.8}{2}(2n-1)\] and \[h=0+\frac{1}{2}(9.8){{n}^{2}}\] \[\Rightarrow \]\[\frac{5}{9}(4.9{{n}^{2}})=4.9(2n-1)\] \[\Rightarrow \]\[5{{n}^{2}}=18n-9\Rightarrow n=3\] (\[\because \]\[n\]cannot be a fraction.) From Eq. (i) \[h=4.9{{n}^{2}}=4.9\times {{(3)}^{2}}=44.1\] Hence, the time of motion is 3s and the height of the tower is 44.1 m.
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