SOLUTION: A boy throws a ball straight up into the air it reaches the highest point of its flight after 4 seconds How fast was the ball going when it left the boys hand

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Question 943272: A boy throws a ball straight up into the air it reaches the highest point of its flight after 4 seconds How fast was the ball going when it left the boys hand
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Using feet and seconds,
+h%28t%29+=+-16t%5E2+%2B+v%2At+
-----------------------
The time coordinate of the
highest point is at:
+-b+%2F+%28+2a+%29+ where
+b+=+v+
+a+=+-16+
+-b%2F%282a%29+=+-v%2F%282%2A%28-16%29%29+
+-b%2F%282a%29+=+v%2F32+
+v%2F32+=+4+
+v+=+128+
The ball was going 128 ft/sec when it
left the boy's hand
-------------------
Here's the plot:
+graph%28+400%2C+400%2C+-2%2C+10%2C+-50%2C+300%2C+-16x%5E2+%2B+128x+%29+
check:
+h%284%29+=+-16%2A4%5E2+%2B+128%2A4+
+h%284%29+=+-256+%2B+512+
+h%5B4%5D+=+256+
Looks about right