SOLUTION: A1. A balloon is rising vertically at a constant speed of 5 ft/sec. A boy is cycling along a straight road at a speed of 15 ft/sec. When he passes under the balloon, it is 45 ft ab

Algebra ->  Testmodule -> SOLUTION: A1. A balloon is rising vertically at a constant speed of 5 ft/sec. A boy is cycling along a straight road at a speed of 15 ft/sec. When he passes under the balloon, it is 45 ft ab      Log On


   



Question 1040093: A1. A balloon is rising vertically at a constant speed of 5 ft/sec. A boy is cycling along a straight road at a speed of 15 ft/sec. When he passes under the balloon, it is 45 ft above him. How fast is the distance between the boy and the balloon increasing 3 seconds later?
Thankyou!

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
When he is directly under the balloon, the distance
between them is changing at +5+ ft/sec because
his speed in the vertical direction is zero
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In 3 sec, ballon is at +5%2A3+=+15+ ft plus +45+ ft
+60+ ft above the boy
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In 3 sec the boy travels +15%2A3+=+45+ ft
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+45%2F60+=+3%2F4+, so this is a 3 - 4 - 5 triangle
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The component of the balloon's speed along the
line between them is:
+%284%2F5%29%2A5+=+4+ ft/sec ( away from the boy )
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The component of the boy's speed along the
line between them is:
+%28+3%2F5+%29%2A15+=+9+ ft/sec
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The distance between them is increasing at
+4+%2B+9+=+13+ ft/sec
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I didn't draw it out, but that would help.
Hope I got it )