SOLUTION: 6. A ball is thrown vertically upward with an initial velocity of 48 feet per second. The ball started from a height of 8 feet off the ground. a. At what time will the rocke

Algebra ->  Rational-functions -> SOLUTION: 6. A ball is thrown vertically upward with an initial velocity of 48 feet per second. The ball started from a height of 8 feet off the ground. a. At what time will the rocke      Log On


   



Question 720469: 6. A ball is thrown vertically upward with an initial velocity of 48 feet per second. The ball started from a height of 8 feet off the ground.
a. At what time will the rocket reach the maximum height? ______________
b. What is the maximum height the ball will reach? _______________
d. Where will the ball be after three seconds? _____________
e. What is the equation for the axis of symmetry? ________________________


Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
The effect of gravity pulling down is +-16t%5E2+ ft/sec2
The effect of upward initial velocity is +48t+ ft/sec
The hight off the ground adds +8+ ft
---------------------------------
The equation is +h+=+-16t%5E2+%2B+48t+%2B+8+
(a) The maximum height is at t+=++-b%2F%282a%29+ for
a parabola ( which this is ), when the form of the
equation is +h+=+at%5E2+%2B+b%2At+%2B+c+
+a+=+-16+
+b+=+48+
+-b%2F%282a%29+=+-48%2F%282%2A%28-16%29%29+
+-b%2F%282a%29+=+1.5+
So, at t = 1.5 sec, the height is a maximum
-------------------
(b)
Plug +t+=+1.5+ back into the equation to find h
+h%5Bmax%5D+=+-16%2A1.5%5E2+%2B+48%2A1.5+%2B+8+
+h%5Bmax%5D+=+-36+%2B+72+%2B+8+
+h%5Bmax%5D+=+44+
The max height is 44 ft
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(d)
In 3 sec, the ball will be
+h+=+-16t%5E2+%2B+48t+%2B+8+
+h+=+-16%2A3%5E2+%2B+48%2A3+%2B+8+
+h+=+-144+%2B+144+%2B+8+
In 3 sec, the ball will be 8 ft off the ground again
---------------------
(e)
The axis of symmetry is a vertical line, and every
point on that line has the same x-value, so
the equation for this line is +x+=+1.5+
Here's the plot of the equation:
+graph%28+400%2C+400%2C+-1%2C+5%2C+-5%2C+50%2C+-16x%5E2+%2B+48x+%2B+8+%29+