Question

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

• A. $R=13.8m$
• B. $R=8m$
• C. $R=12.8m$
• D. $R=9m$

Answer 1

The correct option is C $R=12.8m$

The equation of projectile is given by

$y=16x-\frac{5}{4}{x}^2$

For the horizontal range,, $x=R$

$y=0=16R-\frac{5}{4}{R}^2$

$16R-\frac{5}{4}{R}^2=0$

$R(16-\frac{5}{4}R)=0$

$16-\frac{5}{4}R=0$

$16=\frac{5}{4}R$

$R=\frac{16\times 4}{5}$

$R=12.8m$

The correct option is C.