Q 11-02-018NEETEAMCET 2013 (Medical)Medium
A body is thrown vertically upward from a point 'A' $125$ m above the ground. It goes up to a maximum height of $250$ m above the ground and passes through 'A' on its downward journey. The velocity of the body when it is at a height of $70$ m above the ground is ($g = 10\ \text{m/s}^2$)
Answer: (C) $60$ m/s
Concept. At the maximum height the body is momentarily at rest; from there it falls freely: $v = \sqrt{2gh}$.
Step 1. Distance fallen. $250 - 70 = 180$ m.
Step 2. Speed.
$$v = \sqrt{2 \times 10 \times 180} = 60\ \text{m/s}$$
(The starting point A does not matter.)
Answer. $60$ m/s (Option C).
Solution by Sreeraj P, M.Sc Physics