Question 616643: If an object is propelled upward from a height of s feet at an initial velocity of v feet per second, then it height h after t seconds is given by the equation h=-16t squared +vt+s, where h is in feet. if the object is propelled from a height of 4 feet with an initial velocity of 64 feet per second, its height h is given by the equation h =-16t squared+ 64t+4.
After how many seconds is the height 32 feet?
Answer by lwsshak3(11628)   (Show Source):
You can put this solution on YOUR website! If an object is propelled upward from a height of s feet at an initial velocity of v feet per second, then it height h after t seconds is given by the equation h=-16t squared +vt+s, where h is in feet. if the object is propelled from a height of 4 feet with an initial velocity of 64 feet per second, its height h is given by the equation h =-16t squared+ 64t+4.
After how many seconds is the height 32 feet?
**
h =-16t squared+ 64t+4
32=-16t^2+64t+4
set equation=0
0=-16t^2+64t+4-32
0=-16t^2+64t-28
divide by 4
0=-4t^2+16t-7
4t^2-16t+7=0
(2t-7)(2t-1)=0
t=1/2 sec (object on the way up)
or
t=7/2 sec (object on the way down)
ans:
object is at a height of 32 ft after 1/2 sec and 7/2 sec
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