Question

The height of a projectile launched upward at a speed of 48 feet/second from a height of 160 feet is given by the function h(t)=-16sup(t,2)+48t+160. How long will it take the projectile to hit the ground?

Answer 1

Hello,

5 s

Explanation:

`h(t)=-16t^2+48t+160\\=-16(t^2-3t-10)\\=-16(t^2-5t+2t-10)\\=-16(t(t-5)+2(t-5))\\=-16(t-5)(t+2)\\\\h(t)=0 \Longleftrightarrow\ t=-2\ or\ t=5\\\\Only\ t=5\ is \ a\ answer.(time\ must\ be\ positive)`