This is a follow-up to Part 1 . The mad scientist enjoys his first flight so much that he hurriedly prepares his suit for a second flight. In the process, he accidentally bumps the dial which controls the parameter.
The launch parameters for the second flight are identical to those of the first flight, except for . This time, the poor scientist stays in the air for some time before crash landing (at ground level) 1000 meters from the launch point.
To what value did the scientist accidentally adjust (to one decimal place)?
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From our previous problem:
v x = 1 0 e ( α / 1 5 0 ) t
v y = ( 1 5 0 0 / α ) + ( 2 0 − 1 5 0 0 / α ) e ( α / 1 5 0 ) t
Integrating with respect to time, and considering that at t = 0 both x and y are equal to 0 :
x = ( 1 5 0 0 / α ) e ( α / 1 5 0 ) t
y = ( 1 5 0 0 / α ) t + ( 3 0 0 0 / α − 2 2 5 0 0 0 / α 2 ) e ( α / 1 5 0 ) t
We want x to be 1 0 0 0 while y is 0 . So, for x :
( 1 5 0 0 / α ) e ( α / 1 5 0 ) t = 1 0 0 0
( i ) e ( α / 1 5 0 ) t = 2 α / 3
Also, for y :
( 1 5 0 0 / α ) t + ( 3 0 0 0 / α − 2 2 5 0 0 0 / α 2 ) e ( α / 1 5 0 ) t = 0
Plugging (i) on this:
( 2 2 5 0 0 0 / α 2 − 3 0 0 0 / α ) ( 2 α / 3 ) = ( 1 5 0 0 / α ) t
( i i ) t = 3 3 0 0 − 4 α
Plugging (ii) in (i):
e 4 5 0 ( 3 0 0 − 4 α ) α = 3 2 α
I've solved this numerically (if there's a different solution, I'm happy to see), and obtained:
α = 6 8 . 7 4