A ball falls from a height of 18m above the ground. Find the speed with which the ball hits the ground. \([g = 10ms^{-2}]\)
- 9\(ms^{-1}\)
- 9.49\(ms^{-1}\)
- 13.42\(ms^{-1}\)
-
18.97\(ms^{-1}\)
The correct answer is: D
Explanation
Due to conservation of energy, K.E = P.E
\(\frac{1}{2}mv^{2} = mgh\)
\(\implies m \times 10 \times 18 = \frac{1}{2}mv^{2}\)
\(v^{2} = 2 \times 10 \times 18 = 360\)
\(v = \sqrt{360} = 18.97ms^{-1}\)