document.write( "Question 263100: Starting from rest, a boulder rolls down a hill with constant acceleration and travels 2.00m during the first second.
\n" ); document.write( "How far does it travel during the second second?
\n" ); document.write( "How fast is it moving at the end of the first second?
\n" ); document.write( "How fast is it moving at the end of the second second? \n" ); document.write( "

Algebra.Com's Answer #193827 by drk(1908) $\"\"$ $\"About$

You can put this solution on YOUR website!
One formula we can use is
\n" ); document.write( "(i) $\"h%28t%29+=+-9.8t%5E2+%2B+V%28sub+0%29+t+%2B+S%28sub+0%29\"$
\n" ); document.write( "we know that v(sub0) = 0
\n" ); document.write( "and if t= 1 then h(1) = 2
\n" ); document.write( "so, w get
\n" ); document.write( "2 = -9.8(1)^2 + S(sub0)
\n" ); document.write( "S(sub0) = 11.8
\n" ); document.write( "---
\n" ); document.write( "Our equation becomes
\n" ); document.write( "(ii) $\"h%28t%29+=+-9.8t%5E2+%2B+11.8\"$
\n" ); document.write( "take a derivative to get speed as
\n" ); document.write( "(ii) s(t) = -19.6t
\n" ); document.write( "take another derivative to get acceleration as
\n" ); document.write( "(iii) a(t) = -19.6
\n" ); document.write( "---
\n" ); document.write( "in the second second, we get
\n" ); document.write( "h(2) = -9.8*2^2 + 11.8
\n" ); document.write( "h(2) = -27.4 or 27.4 feet down hill.
\n" ); document.write( "---
\n" ); document.write( "how fast at end of second second sounds like average speed or
\n" ); document.write( "average = (h(2)-h(1)) / (2-1)
\n" ); document.write( "or
\n" ); document.write( "average = (-27.4-2)/1 = -29.4
\n" ); document.write( "---
\n" ); document.write( "how fast at end of first second sounds like average speed or
\n" ); document.write( "average = (h(1)-h(0)) / (1-0)
\n" ); document.write( "or
\n" ); document.write( "average = (2-11.8)/1 = -8.2
\n" ); document.write( "--- \n" ); document.write( "

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