Use g=10 N/kg in this assignment.
1. What is the gravitational energy (relative to the unstretched surface of the trampoline) of the 20 kg ball at its apex 2 m above the trampoline?
2. What is the kinetic energy of the ball just before impacting the trampoline?
3. At maximum stretch at the bottom of the motion, what is the sum of the elastic and gravitational energy of the ball?
4. What conclusions can be drawn from the answers above
I’m not sure how to answer #3 of this problem. I know that the potential is mgh , where h would be 2+x, and that the elastic is 0.5kx^2 , but i don’t know what k is. I also know that energy is conserved so the kinetic energy right before it hits the trampoline should be the same as the sum i get here but i don’t really know how to do this question without making that assumption first. How do i approach this question?
3. At maximum stretch at the bottom of the motion, what is the sum of the elastic and gravitational energy of the ball?
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The same as #1.
The sum of potential and kinetic energy is constant throughout this problem. The ball has stopped, no kinetic, so that is it.