An arrow is shot vertically upward from a platform 27ft high at a rate of 225ft/sec. When will the arrow hit the ground? Use the formula: h=−16t2+v0t+h0. (Round your answer to the nearest tenth.)

Answer 1

h-16t^2 + 225t + 27 = 0 for h=0, ground level when it hits the ground

16t^2 -225t -27 = 0

factor if you can, or else complete the square or use the quadratic formula

t = 225/32 + (1/32)sqr(225^2 + 64(27))

= (225 + sqr(50625+1728))/32

= (225+ sqr52353)/32

= about (225+228.8)/32

= 453.8/32

=about 14.18 seconds to hit the ground

= about 14.2 seconds, rounded off to nearest tenth of a second

h(t) =-16t^2 + 225t +27

h'(t) = -32 +225 = 0

t = 225/32 = about 7 seconds to reach max height

to hit ground would be twice that, if it started at ground level

add a little more, 14+ seconds if it starts higher up as in 27 feet