document.write( "Question 56060: 1. A person dives from a 30 foot platform with an initial velocity of
\n" ); document.write( "> 5 feet per second (upward)
\n" ); document.write( ">
\n" ); document.write( "> a. Find the position of the function
\n" ); document.write( "> b. How long will it take for the diver to hit the water?
\n" ); document.write( "> c. What is the diver's velocity at impact?
\n" ); document.write( "> d. What is the diver's acceleration at impact?
\n" ); document.write( "
\n" ); document.write( "

Algebra.Com's Answer #38032 by jenrobrody(19)\"\" \"About 
You can put this solution on YOUR website!
For a falling body problem, use the function:
\n" ); document.write( "\"f%28x%29=0.5ax%5E2%2Bbx%2Bc\"
\n" ); document.write( "where a represents the acceleration due to gravity= -32 ft/sec^2
\n" ); document.write( "b represents initial velocity= 5
\n" ); document.write( "c represents initial height= 30
\n" ); document.write( "(notice that up is positive and down is negative here)
\n" ); document.write( "the function f(x)= -16x^2+ 5x + 30, gives the position of the diver at time t.
\n" ); document.write( "Note that if x=0, f(0) = 30. ie, the diver is 30 feet above water at t=0.
\n" ); document.write( "We need to find time=x when f(x)=0. ie, at zero height above water.
\n" ); document.write( "Sovle for x:
\n" ); document.write( "\"-16x%5E2%2B5x%2B30=0\"
\n" ); document.write( "\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"
\n" ); document.write( "\"x+=+%28-5+%2B-+sqrt%28+5%5E2-4%28-16%29%2830%29%29%29%2F%282%28-16%29%29+\"
\n" ); document.write( "\"x+=+%28-5+%2B-+sqrt%28+25%2B1920%29%29%2F-32+\"
\n" ); document.write( "\"x+=+%28-5+%2B-+44.1%29%2F-32\"
\n" ); document.write( "x = -49.1/-32 or 39.1/-32
\n" ); document.write( "x = 1.5 or -1.2 seconds
\n" ); document.write( "Use the positive answer for time after jumping.
\n" ); document.write( "For the velocity, use the equation(same constants a,b,c as above):
\n" ); document.write( "\"g%28x%29=ax%2Bb\"
\n" ); document.write( "or g(x)=(-32)x+5 = -32x + 5
\n" ); document.write( "where g(x) represents the velocity after x seconds.
\n" ); document.write( "Find velocity after 1.5 seconds:
\n" ); document.write( "g(1.5) = -32(1.5) + 5 = -43 feet/sec
\n" ); document.write( "For acceleration, h(x)= a or, h(x)= -32 feet/sec^2
\n" ); document.write( "acceleration is a constant and equals -32 feet/sec^2.
\n" ); document.write( "
\n" ); document.write( "
\n" );