Q. A child stands on the edge of the cliff $10\, m$ above the ground and throws a stone horizontally with an initial speed of $5 \,ms ^{-1}$. Neglecting the air resistance, the speed with which the stone hits the ground will be ______$ms ^{-1}$ (given, $g=10 \,ms ^{-2}$ ).
Solution:
Correct answer is (a) 15
