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Rectinilear motion

  • Thread starter chukie
  • Start date
  • #1
80
0
Sara launches a model rocket in an open field near her house. Its trajectory is described by the function y=60ln(x+1)-6x for x=[0,36.15] where y is the rocket's height (in feet) above the ground and x is the horizontal distance (in feet) between the launch site and a point directly below the rocket.

Given that the rocket's horizontal velocity (dx/dt) is 50 ft/s when it's directly over a point 20 (horizontal) feet from the launch site, determine the rocket's vertical veloctiy (dy/dt) at that point.

I don't know how to go about solving this question, because normally the position is given as a function of time. Can someone help me? Thanks.
 

Answers and Replies

  • #2
378
2
Chain rule!

dy/dt = ?
find this and do value substitutions
 
  • #3
80
0
Chain rule!

dy/dt = ?
find this and do value substitutions
oh yeah!! i was overthinking it way too much. thanks though!
 
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