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What is the elasticity of a ball which hits a wall at 10 m/s and rebounds off the wall at 8 m/s? (answer to 2 significant digits)
That's an online question for school. All of us trying to do it can't get it. It should be 80% I think, but it's not. And it's not a multiple choice question.
Anyone know how you would do that?
5.
What....? 5 is the answer? Huh? I can't make sense out of that...and it should be a two digit number (yes I know how sig figs work but I know that what my teacher implies by that)
64%
8.0x10^-1
How'd you get that?Quote:
Originally posted by ZerOrDie
64%
3X
Now just have to solve for X. :D
e = ( 1 - ((EKInitial - EKFinal) / EKInitial)) *100 = x%
We will substitute any mass. Lets say 1kg.
EK = (1/2)mv^2
EKInitial = (1/2)(1)(10)^2 = 50J
EKFinal = (1/2)(1)(8^2) = 32J
((50 - 32) / 50) * 100 = 36%
1 - .36 = .64
.64 * 100 = 64%
The ball has an elasticity of 64% (as 36% of the Kinetic energy was lost). Just remember your conservation of energy.
:D looks like someone took the time to explain my answer lol
Yes. I had to look back on some previous work because I realized that I actually forgot how to calculate the elasticity of an object - which frusterated me to no end.Quote:
Originally posted by ZerOrDie
:D looks like someone took the time to explain my answer lol
im so mad. I even tried that, but it said it was incorrect so I reverted to 80%! I think it has problems with how you enter the answer, like it'd make a difference if it was 64, 64%, or 64 %
That threw me off then, indeed!
Try .64