document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=802230>Question 802230</A>: <I><SPAN STYLE=\"word-break: break-all;\"> challenge questions<BR>\n" );
document.write( "A stone is thrown vertically upwards, from the ground, with a velocity 49 m/s. After 2 seconds, another stone is thrown vertically upwards from the same place. If both the stone strike the ground at the same time, find the velocity, with which the second stone was thrown upwards. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #483806 by </B><A HREF=/tutors/aboutme.mpl?userid=KMST><B>KMST(5328)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=KMST><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=KMST><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=483806\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The upwards velocity of each stone will decrease due to the acceleration of gravity, g, by 9.8 meter per second each second.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=g=9.8 ALIGN=MIDDLE  ALT=\"g=9.8\"   DISABLED_style= \"max-width:90%; height:auto;\" ><IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=m%2Fs%5E2 ALIGN=MIDDLE  ALT=\"m%2Fs%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" > (rounded)<BR>\n" );
document.write( "The upwards velocity will reach zero and then become a negative number (meaning a downwards velocity) as the stone falls back to the ground.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t ALIGN=MIDDLE  ALT=\"t\"   DISABLED_style= \"max-width:90%; height:auto;\" >= the time of flight of the first stone (in seconds),<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t-2 ALIGN=MIDDLE  ALT=\"t-2\"   DISABLED_style= \"max-width:90%; height:auto;\" >= the time of flight of the first stone (in seconds),<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=h%5Bn%5D ALIGN=MIDDLE  ALT=\"h%5Bn%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" >= height of either stone (in meters)<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=v ALIGN=MIDDLE  ALT=\"v\"   DISABLED_style= \"max-width:90%; height:auto;\" >= initial upwards velocity of the second stone (in m/s)<BR>\n" );
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document.write( "For the first stone, physics and math tell us that the height is<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=h%5B1%5D=49t-9.8t%5E2%2F2 ALIGN=MIDDLE  ALT=\"h%5B1%5D=49t-9.8t%5E2%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" > or <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=h%5B1%5D=49t-4.9t%5E2 ALIGN=MIDDLE  ALT=\"h%5B1%5D=49t-4.9t%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The first stone is on the ground when<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=49t-4.9t%5E2=0 ALIGN=MIDDLE  ALT=\"49t-4.9t%5E2=0\"   DISABLED_style= \"max-width:90%; height:auto;\" >--><IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=4.9%2At%2A%2810-t%29=0 ALIGN=MIDDLE  ALT=\"4.9%2At%2A%2810-t%29=0\"   DISABLED_style= \"max-width:90%; height:auto;\" >--><IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=system%29t=o%2C%22or%22%2Ct=10%29 ALIGN=MIDDLE  ALT=\"system%29t=o%2C%22or%22%2Ct=10%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >.<BR>\n" );
document.write( "That means it is on the ground at the moment it \"is thrown vertically upwards, from the ground,\" and it is on the ground 10 seconds later.<BR>\n" );
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document.write( "For the second stone, physics and math tell us that the height is<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=h%5B2%5D=vt-4.9%28t-2%29%5E2 ALIGN=MIDDLE  ALT=\"h%5B2%5D=vt-4.9%28t-2%29%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "We want it to hit the ground <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=h=0 ALIGN=MIDDLE  ALT=\"h=0\"   DISABLED_style= \"max-width:90%; height:auto;\" > at <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t=10 ALIGN=MIDDLE  ALT=\"t=10\"   DISABLED_style= \"max-width:90%; height:auto;\" >, just like the first stone, so<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=v%2A10-4.9%2A8%5E2=0 ALIGN=MIDDLE  ALT=\"v%2A10-4.9%2A8%5E2=0\"   DISABLED_style= \"max-width:90%; height:auto;\" >--><IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=10v-313.6=0 ALIGN=MIDDLE  ALT=\"10v-313.6=0\"   DISABLED_style= \"max-width:90%; height:auto;\" >--><IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=10v=313.6 ALIGN=MIDDLE  ALT=\"10v=313.6\"   DISABLED_style= \"max-width:90%; height:auto;\" >--><IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=v=31.36 ALIGN=MIDDLE  ALT=\"v=31.36\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "So <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%28v=31%29 ALIGN=MIDDLE  ALT=\"highlight%28v=31%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >m/s (rounded because 9.8m/s^2 was a rounded number for g, 49m/s was given with only 2 significant digits, and I am in scientist mode now). </SPAN>\n" );
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