A stone is thrown vertically upwards and its height at any time t seconds is...
FURTHER MATHEMATICS
WAEC 2010
A stone is thrown vertically upwards and its height at any time t seconds is \(h = 45t - 9t^{2}\). Find the maximum height reached.
- A. 45. 25 m
- B. 45.50 m
- C. 56.00 m
- D. 56.25 m
Correct Answer: D. 56.25 m
Explanation
\(h = 45t - 9t^{2}\)
\(\frac{\mathrm d h}{\mathrm d t} = 45 - 18t = 0\)
\(45 = 18t \implies t = 2.5 s\)
\(h(2.5) = 45(2.5) - 9(2.5)^{2} = 112.5 - 56.25\)
= \(56.25 m.\)
Post an Explanation Or Report an Error
If you see any wrong question or answer, please leave a comment below and we'll take a look. If you doubt why the selected answer is correct or need additional more details? Please drop a comment or Contact us directly. Your email address will not be published. Required fields are marked *