Question

A stone falls freely under gravity. It covers distances $h_1,h_2$ and $h_3$ in the first $5$ seconds, the next $5$ seconds and the next $5$ seconds respectively. The relation between $h_1,h_2$ and $h_3$ is

• A. $h_1=2h_2=3h_3$
• B. $h_1=\frac{h_2}{3}=\frac{h_3}{5}$
• C. $h_2=3h_1$ and $h_3=3h_2$
• D. $h_1=h_3=h_3$

Answer 1

Answer: (B)

$h_1=\frac{h_2}{3}=\frac{h_3}{5}$

$h_1=\frac{1}{2}g{t}^2=\frac{1}{2}\times 10\times 5^2=125$

$h_2=\frac{1}{2}\times 10\times {10}^2-\frac{1}{2}\times 10\times 5^2=375$

$h_3=\frac{1}{2}\times 10\times {15}^2-\frac{1}{2}\times 10\times {10}^2=625$

Hence $h_1=\frac{h_2}{3}=\frac{h_3}{5}$