erniepower
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Has anyone else looked at this problem? I beleive the solution in the book takes the wrong approach.
I believe this should be a conservation of energy problem. Not a constant acceleration problem. You can calculate the needed takeoff velocity using the projectile motion equations. That seems simple enough. Then the book uses that takeoff velocity, and initial velocity of 0 and and acceleration time of 1 sec to calculate an acceleration and from that a force. Then they use this force to find the number of springs needed. I think they assume that the force calculated would be constant through the release of the spring but as soon as the balloon starts to move, the force will be less because the displacement of the spring will be less.....
I think you will have to find the kinetic energy of the balloon at take off, and set it equal to the potential energy stored in the springs to find the total number of springs.
If I am off my rocker, let me know.....
I believe this should be a conservation of energy problem. Not a constant acceleration problem. You can calculate the needed takeoff velocity using the projectile motion equations. That seems simple enough. Then the book uses that takeoff velocity, and initial velocity of 0 and and acceleration time of 1 sec to calculate an acceleration and from that a force. Then they use this force to find the number of springs needed. I think they assume that the force calculated would be constant through the release of the spring but as soon as the balloon starts to move, the force will be less because the displacement of the spring will be less.....
I think you will have to find the kinetic energy of the balloon at take off, and set it equal to the potential energy stored in the springs to find the total number of springs.
If I am off my rocker, let me know.....
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