A stone is released from a height of 80m above the ground. Calculate its velocity just before it strikes the ground. (g = 10ms\(^{-2}\))
A
25ms-1
B
40 ms-1
C
55 ms-1
D
65ms-1
E
80 ms-1
Verified Correct Answer: B.
Physical Principles & Numerical Solution
Velocity before reaching the ground ( v ) = \(\sqrt{2gH}\) from the third equation of motion.
v = \(\sqrt{2 \times 10 \times 80}\) = \(\sqrt{1600}\) = 40m/s
Source: Myschool Past Questions Archive (Record #42921)