Question

A stone is dropped from the peak of a hill. It covers a distance of 30m in last second of its motion. What is height of the peak?

Answer 1

what does this question mean i dont understand it?

Answer 2

$\sf\:h \: = \: ut \: \: + \: \: \frac{1}{2} \times \: g \: \times t {}^{2} \\ \\ 30 \: \: \: = \: 0 \: \: \: + \: \: \sf\frac{1}{2} \: \times \: g \: (2t - 1) \\ \\ from \: equation \: 2 \\ \\ 30 \: \: = \: \: \frac{1}{2} \: \: \times \: \: 9.8 \: \: \times 2t - 1 \\ \\ 2t - 1 \: \: = \: \: \frac{30}{4.9} \\ \\ 2t \: \: = \: \frac{30}{4.9} + 1 \\ \\ \boxed {t \: \: = \: \: 3.56 \: s} \\ \\ \texttt inserting \: value \: of \: t \: in \: eq \: \: 1 \\ \\ h \: \: = \: \: \frac{1}{2} \: \: \times \: g \: \times t {}^{2} \\ \\ h \: \: = \: \: \frac{1}{2} \times 9.8 \times 3.56 \times 3.56 \\ \\ \bf\boxed {h \: \: = \: \: 62.1 \: m}$