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Home Q & A Board Science-Related Homework Help Physics
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nvr8884 nvr8884
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11 years ago
How can i use the work energy principle to find the velocity of a ball (moving as a projectile) right before it hits a box on the ground. I know distance traveled by the box, but i don't know the time it took. I have tried using the impulse momentum equation to solve for different variables but I still have 2 variables and it isn't working.
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wrote...
#1
11 years ago
1/2*mass*velocity^2=mass*gravity*height
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#2
11 years ago
I assume you know your formulas, for potential energy due to gravity, and kinetic energy.

find initial potential energy
final kinetic energy before impact will equal this initial potential energy (if we assume air resistance negligible)
this is a conclusion drawn from the conservation of energy.

equate the equations for final kinetic, and initial potential energies
1/2 mv^2 = mgh
masses will cancel, and you should have
v= sqrt (2gh)
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