Physics problem, basketball dunk (Hookes law)

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SUMMARY

The discussion centers on calculating the bend of a basketball rim when a 95 kg player hangs onto it, using Hooke's Law with a spring constant of 7400 N/m. The correct approach involves determining the static extension of the rim under the weight of the player, leading to the equation 95 kg * 9.81 m/s² = k * x, where k is the spring constant. The accurate solution for the extension x is 0.25 m, while the book incorrectly states it as 0.15 m. The confusion arises from misapplying kinetic energy concepts instead of focusing solely on static equilibrium.

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Homework Statement


A 95kg basketball player slam dunks a basketball and hangs onto the rim. Find out how much the rim bends if its spring constant = 7400 N/m and the basketball rim is 2 m in the air.

Homework Equations


Ep = 0.5 k x^2
Ek = 0.5 m v^2
Eg = mgh

The Attempt at a Solution


The book got 0.15 m. My answer is way off, what did I do wrong? I think this should be right.

Ep1 + Ek1 + Eg1 = Ep2 + Ek2 + Eg2
Ep1 = 0, Ek1 = 0, Ek2 = 0

Eg1 = Ep2 + Eg2
mgh = (1/2)kx^2 + mg(2m - x)

1862 J = 3700x^2 N/m + 1862 J - 931x N

3700x^2 N/m - 931x N = 0

931x N( 3.97x / m - 1 ) = 0

x = 0 or 3.97x/m = 1

x = 1/(3.97/m) = 0.25 m.

Book got 0.15. My answer is way off and I'm not sure why it could be look this. Is my logic correct? Am I correct?
 
Last edited:
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It is not entirely clear, but I don't think it is asking the maximum extent of the bend under SHM. It's a statics question: if the player hangs on for an arbitrarily long time, what will the extent of the bend settle out at?
 
You are not given any speeds so there is no point in looking at kinetic energy. The problem is just "if a 95 kg object is hung from a spring with spring constant 7400 N/m, how far will the spring extend?"

95g=
 

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