Question

The equation of a projectile is $y=(10x-\frac{5x^2}{4})m$. The maximum height achieved by the projectile is

• A. $4m$
• B. $20m$
• C. $40m$
• D. $24m$

Answer 1

The correct option is A $4m$

The equation of a projectile is given by

$y=10x-\frac{5}{4}{x}^2$

For maximum height, $\frac{dy}{dx}=0$

$\frac{d(10x-\frac{5x^2}{4})}{dx}=0$

$10-2\times \frac{5}{4}x=0$

$10-2.5x=0$

$x=\frac{10}{2.5}$

$x=4m$