A Daredevil Jumps Off A Tall Building. He Falls Freely For Several Seconds Before Releasing His Parachute . His Height (h) In Meters , T Seconds After Jumping Can Be Modeled By : h=-4.9t^2+t+360 before he releases his parachute and h=-4t+142 After He Releases His Parachute . How Long After Jumping Did He Release His Parachute ? HELPP ME PLEASE !!!!

Question

A Daredevil  Jumps Off A Tall Building. He Falls Freely For Several Seconds Before Releasing His Parachute . His Height (h) In Meters , T Seconds After Jumping Can Be Modeled By : h=-4.9t^2+t+360 before he releases his parachute and h=-4t+142 After He Releases His Parachute . How Long After Jumping Did He Release His Parachute ? HELPP ME PLEASE !!!!

anonymous · Answer

PLEASE HELP ! THIS IS A BIG QUESTION WORTH LOSTS OF POINTS

noelgreco · Answer

Although it doesn't say so, the second equation suggests he's landed.  Solve for t.

anonymous · Answer

Ok So -4.9t + t + 360=4t +142

noelgreco · Answer

Actually, I put my glasses on an d saw that all you have to do is assume the h valuues are the same, equate the to equations, and solve for t

anonymous · Answer

im confused

irishboy123 · Answer

you have 
$ h_1=-4.9t^2+t+360$
$h_1(0) = 360$
he jumped off a 360m tall building

and then you have 
$h_2=-4t+142$
$h_2(0) = 142$
he pulled the chute at 142 m above ground

so go back to $h_1(t)$ and work out how long it took him to fall from 360m to 142m

you have a quadratic to solve