Question 1111603
an object is projected straight up with an initial velocity of k ft. /sec.
 The height of the object, h, at any time, t, is given by the function h(t)= -16t^2+ kt.
 if the object returns to the ground at t=8 sec., find the height (in feet) of the object at t=7 sec.
Explain in words your steps to finding the value of k.
:
When it hits the ground h(t) = 0, when t = 8
-16(8^2) + 8k = 0
-16(64) + 8k = 0
-1024 + 8k
8k = 1024
k = 1024/8
k = 128
"find the height when t = 7 sec
h(t) = -16(7^2) + 128(7)
h(t) = -784 + 896
h(t) = 112 ft, height at 7 sec