A ball is thrown into the air with an initial upward velocity of 45 ft/s. The height (h) in feet is given by the equation below. After about how many seconds will the ball hit the ground?

Question

anonymous · Answer

h=-16t^2+45t+6

nnesha · Answer

t represent  time 
h = height 
what would be the height when ball hit the ground ?

nnesha · Answer

|dw:1430577047081:dw|
height = ?

anonymous · Answer

t?

nnesha · Answer

t = time we need to find time 
but when ball hits the ground h  =0 
so replace h by 0 $$\huge\rm 0=-16t^2+45t+6$$ and now solve for t 
you can use quadratic formula  $$ \huge\rm \frac{ -b \pm \sqrt{b^2 - 4ac} }{ 2a }$$

nnesha · Answer

a b c 
Ax^2 +Bx +C = 0