Raindrops of mass 5 x 10^-7 Kg fall vertically in still air with a uniform speed of 3m/s.
If such drops are falling when a wind is blowing with a speed of 2m/s, what is the angle which the paths of the drops make with the vertical?
Answer: 33.7 degrees
*How do you solve this when you don’t know which direction the wind is blowing from?
(English is not my mother-tongue.)
The question does not give a wind direction only the velocity
of 2m/s so the question is what angle the path of the drops
make with the vertical,you know the velocity of the rain drop
is 3m/s if you draw a right angle triangle 3 unit down and
2 units horizontal, draw a line to meet that is the hypotenuse
call horizontal line ( b ) vertical line ( a )
Tan A = b / a = 2 / 3 = 0.6666, Tan table 0.6666 = 33 .7 deg
Hope that works out alright
March 17th, 2010 at 5:42 pm
The wind, I suspect, is ASSUMED to be blowing horizontally. ie ‘across’ the raindrops (90degrees to vertical/the direction of rainfall).
References :
March 17th, 2010 at 6:18 pm
The question does not give a wind direction only the velocity
of 2m/s so the question is what angle the path of the drops
make with the vertical,you know the velocity of the rain drop
is 3m/s if you draw a right angle triangle 3 unit down and
2 units horizontal, draw a line to meet that is the hypotenuse
call horizontal line ( b ) vertical line ( a )
Tan A = b / a = 2 / 3 = 0.6666, Tan table 0.6666 = 33 .7 deg
Hope that works out alright
References :