document.write( "Question 983054: An auto travels at the rate of 35-km/h, N for 6.0mins, then NE for 7.0mins and finally at 20-km/h, S for 8.0mins. what is the average velocity of the auto? Whta is the average speed of the auto? \n" ); document.write( "
Algebra.Com's Answer #604007 by KMST(5328)\"\" \"About 
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It is not clearly specified,
\n" ); document.write( "but it seems like after going N for 6.0 minutes at 35 km/h,
\n" ); document.write( "the auto continues NE for 7.0 minutes at the same speed.
\n" ); document.write( "That is what I will assume.
\n" ); document.write( "The whole trip looks like this:
\n" ); document.write( "The average velocity is a vector with magnitude and direction,
\n" ); document.write( "and can be found as the start-end displacement vector divided by the travel time.
\n" ); document.write( "The average speed is a scalar quantity (a number with units of km/h),
\n" ); document.write( "and can be found as the total distance covered along the trajectory divided by the travel time.
\n" ); document.write( "The distances traveled are as follows:
\n" ); document.write( "\"red%28%22N+%3A%22%29\" \"%2835km%2F%2260+minutes%22%29%2A%286minutes%29=3.5km\"
\n" ); document.write( "\"green%28%22NE+%3A%22%29\" \"%2835km%2F%2260+minutes%22%29%2A%287minutes%29=49%2F12\"\"km=4.083km\"(rounded)
\n" ); document.write( "\"blue%28%22S+%3A%22%29\" \"%2820km%2F%2260+minutes%22%29%2A%288minutes%29=8%2F3\"\"km=2.667km\"(rounded).
\n" ); document.write( "Now the trips looks like this:
\n" ); document.write( "The approximate total distance traveled is
\n" ); document.write( "\"3.5km%2B4.083km%2B2.667km=10.250km\" .
\n" ); document.write( "The total travel time is
\n" ); document.write( "\"6minutes%2B7minutes%2B8minutes=21minutes\" .
\n" ); document.write( "The average speed of an auto that travels a total of \"10.250km\" in \"21minutes\" is
\n" ); document.write( "\"%2810.250km%2F%2221minutes%22%29%2860minutes%2F%221hour%22%29=29.29\"\"%22km+%2F+h%22=29\"\"%22km+%2F+h%22\" (rounded).
\n" ); document.write( "The eastward displacement is the horizontal leg of an isosceles right triangle with a hypotenuse of \"49%2F12\"\"km=4.083km\"(rounded).
\n" ); document.write( "It's measure in km is \"x\" and \"2x%5E2=%2849%2F12%29%5E2=49%5E2%2F12%5E2\" ,
\n" ); document.write( "so \"x%5E2=49%5E2%2F%282%2A12%5E2%29\"---> .
\n" ); document.write( "That is also the vertical leg of the same isosceles right triangle,
\n" ); document.write( "which is the northward displacement during the NE portion of the trip.
\n" ); document.write( "The total (approximate) northward displacement in km is
\n" ); document.write( "\"3.5%2B2.887-2.667=3.72\" .
\n" ); document.write( "Now the trips looks like this:
\n" ); document.write( "The magnitude of the displacement (in km) is approximately
\n" ); document.write( "\"sqrt%283.72%5E2%2B2.887%5E2%29=4.709\" .The
\n" ); document.write( "The approximate) magnitude of the average velocity is
\n" ); document.write( "\"%284.709km%2F%2221minutes%22%29%2860minutes%2F%221hour%22%29=13.45\"\"%22km+%2F+h%22=13.5\"\"%22km+%2F+h%22\" (rounded),
\n" ); document.write( "and \"red%28theta%29\" gives us the direction.
\n" ); document.write( "\"tan%28red%28theta%29%29=2.887%2F3.72=0.7761\"--->\"red%28theta%29=37.8%5Eo\" ,
\n" ); document.write( "so the direction is \"37.8%5Eo\" East of North.
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