A ball is launched into the sky at 272 feet per second from the roof of a skyscraper 1,344 feet tall. The equation for the ball’s height h at time t seconds is h = -16t2 + 272t + 1344. When will the ball strike the ground?
Accepted Solution
A:
The ball will strike the ground when h=0. -16t²+272t+1344=0 t₁,₂=(-272+-√(272²+4*16*1344))/2*(-16) t₁,₂=(-272+-400)/(-32) t₁=(-272+400)/(-32)=-4 or t₂=(-272-400)/(-32)=21 Time cannot be negative value so t₂ is solution. The ball will strike the ground in 21seconds.