Question
Mon April 07, 2014 By: Sangeeta Mandal

 

Expert Reply
Wed April 09, 2014
1) Horizontal range is directly proportional to the square of the speed. If the speed  of A is doubled, horizontal range will increase 4 times. Hence the new ratio of horizontal range will be 12 : 1.
 
2) Let at any instant, the particle is at P and velocity is y.
Then, 
ux = u cos θ          uy = u sin θ
ax = 0                   ay = -g
and,
yx = ux + axt          yy = ux + ax
yx = u cos θ           yy = u sin θ - gt
 
The velocity of projectile, 
 y equals square root of y subscript x squared plus y subscript y squared end root equals square root of u squared cos squared theta plus left parenthesis u space sin theta minus g t right parenthesis squared end root y equals square root of u squared minus 2 u g t space sin theta space plus g squared t squared end root  tan alpha space equals space fraction numerator u space sin theta space minus g t over denominator u space cos theta end fraction
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