document.write( "Question 485107: a long distance runner has an average speed of 5 m/s during a race. how far does the runner travel in 25 minutes? express the answer in m, km, and miles. \r
\n" ); document.write( "\n" ); document.write( "and lastly, \r
\n" ); document.write( "\n" ); document.write( "A rock is dropped off the side of a bridge and hits the water below at 2.5 s later. what is the rocks velocity when it hits the water, the average velocity as it fell and the height of the bridge above the water.
\n" ); document.write( "

Algebra.Com's Answer #331833 by solver91311(24713)\"\" \"About 
You can put this solution on YOUR website!
\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Your second problem:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "You need to choose the measurement system you want to use. Acceleration due to gravity in kms is , whereas in fps it is . The values are negative because of the convention that up is positive.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "I'm just going to do the problem using and then you can substitute the appropriate acceleration value and do the arithmetic.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "The instantaneous velocity of a falling body is the integral of acceleration with respect to time plus a constant which is the initial velocity, \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Since the rock was dropped we can presume that \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Which is to say\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Substitute 2.5 seconds for the time because that is what is given and multiply by the appropriate value of . If you use your answer will be in meters per second, but if you use then your answer will be in feet per second.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "The height is determined by integrating velocity as a function of time. Very conveniently the function we just evaluated to find the final velocity.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Where the constant of integration is the initial height, \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "For simplicity's sake, we will take the initial height to be zero and then consider the surface of the water to be some negative height.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Again, we substitute 0 for the initial values and get:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "And again, substitute 2.5 for and your chosen value for \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "John
\n" ); document.write( "
\n" ); document.write( "My calculator said it, I believe it, that settles it
\n" ); document.write( "
\"The

\n" ); document.write( "
\n" ); document.write( "
\n" );