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## Homework Statement

If a rubber ball is dropped from the height of 120 cm from the floor, and rebounds to a height of 80 cm, what is the value of e, the coefficient of restitution? Show your reasoning and justify your solution.

initial distance 1= 120 cm

final distance 1= 0 cm

initial distance 2 = 0 cm

final distance 2 = 80 cm

acceleration = gravity = -9.8 m/s^2

initial velocity 1 = 0 m/s

final velocity 2 = 0 m/s

## Homework Equations

Not very sure... I honestly don't know how to find the numerical answer here.

e = (vf1/vi1)

## The Attempt at a Solution

I can't come up with a number solution. I do have a justification, though. e will be less than 1 for sure because energy was lost during the rebound. You can tell energy was lost because the ball did not bounce back to original height. It's inelastic and not elastic, so e will not be equal to 1, and the energy is not fully conserved.

Now determining the value of e is where I'm stuck, unless that's impossible.

Thank you for any and all help!