A bad punter on a football team kicks a football approximately straight upward with an initial velocity of 7f ft/sec

Question

a) If a ball leaves his foot at a height of 4 foot, write an equation that models the vertical height s (in feet) of the ball t seconds after being kicked

b) How long will it take for the football to hit the ground?

Answer 1

(a)

h(t) = -(1/2)gt² + v₀t + h₀

g = 32 ft/s²

v₀ = 7 ft/s

h₀ = 4 ft

h(t) = -16t² + 7t + 4

(b)

Set h(t)=0 and solve for t using the quadratic formula. You will get a positive and a negative solution. Since time starts at t=0, the positive solution is the correct one.