Question

The equation of projectile is$y = 16x - \frac{5x^{2}}{4}$. The horizontal range is

• A. 16 m
• B. 8 m
• C. 3.2 m
• D. 12.8 m

Answer 1

Answer: (D)

12.8 m

Answer 2

Standard equation of projectile motion

$y = x\tan\theta\left\lbrack 1 - \frac{x}{R} \right\rbrack$

Given equation : $y = 16x - \frac{5x^{2}}{4}$or $y = 16x\left\lbrack 1 - \frac{x}{64/5} \right\rbrack$

By comparing above equations $R = \frac{64}{5}$ =12.8 m.