SOLUTION: Shelly throws her keys up into the air, releasing them from a height of 4 ft. above the ground with an initial velocity of 32 ft/sec. a. Write and equation representing the hei

Algebra ->  Rational-functions -> SOLUTION: Shelly throws her keys up into the air, releasing them from a height of 4 ft. above the ground with an initial velocity of 32 ft/sec. a. Write and equation representing the hei      Log On


   

Question 558732: Shelly throws her keys up into the air, releasing them from a height of 4 ft. above the ground with an initial velocity of 32 ft/sec.
a. Write and equation representing the height of the keys in terms of time?


Above on the WS it gives two equations for velocity both equaling h-height. This is why i am confused.
Found 2 solutions by ankor@dixie-net.com, Earlsdon:
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Shelly throws her keys up into the air, releasing them from a height of 4 ft. above the ground with an initial velocity of 32 ft/sec.
a. Write and equation representing the height of the keys in terms of time?
h(t) = -16t^2 + 32t + 4
:
graphically
+graph%28+300%2C+200%2C+-1%2C+4%2C+-10%2C+30%2C+-16x%5E2%2B32x%2B4%29+

Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Start with the function for the height, as a function of time, (h(t), of an object propelled upwards from an initial height of h%5B0%5D with an initial velocity of v%5B0%5D.
h%28t%29+=+-%281%2F2%29gt%5E2%2Bv%5B0%5Dt%2Bh%5B0%5D where: g (acceleration due to gravity) = 32ft/sec.squared.
h%28t%29+=+-16t%5E2%2Bv%5B0%5Dt=h%5B0%5D Substitute: v%5B0%5D+=+32 and h%5B0%5D+=+4.
h%28t%29+=+-16t%5E2%2B32t%2B4 Note that the negative comes from the fact that gravity is acting downward.