• # question_answer 40) The equation of projectile is $y=16x-\frac{5{{x}^{2}}}{4}$ The horizontal range is- A) 16 m                B) 8 mC) 3.2 m               D) 12.8 m

$\because \,\,\,y=x\,\tan \,\theta \left( 1-\frac{x}{R} \right)\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,.....(1)$ $and\,\,y\,\,=\,\,16x-\frac{5{{x}^{2}}}{4}$ $\Rightarrow \,\,\,\,\,y\,\,=\,\,16x\,\,\left( 1-\frac{5x}{64} \right)\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,.....(2)$ $comparing\text{ }\left( 1 \right)\,\,\And \,\,\left( 2 \right),\text{ }R=\frac{64}{5}=12.8\text{ }m$