Energy conservation of a light spring

AI Thread Summary
The discussion centers on the energy conservation of a ball released onto a light spring fixed in a vertical tube. It examines three statements regarding the relationship between the ball's mass, the height from which it falls, and the energy stored in the spring. The key points include that the compression of the spring is proportional to the mass of the ball, the compression is independent of the initial height, and the gravitational potential energy lost equals the strain energy stored in the spring. Internal friction within the spring dissipates some energy as heat, which contributes to the ball eventually coming to rest. Overall, the equilibrium condition between gravitational and spring forces explains the observed behavior.
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Homework Statement



A light spring is fixed to the bottom of a vertical tube.A ball is released from rest at a height h above the upper end of the spring as shown.After rebounding several times the ball eventually comes to rest and stay on top of the spring.Assume all contact surfaces are smooth and the spring obeys Hooke's law throughout.Which of the following statement is/are true?

(1)The compression of the spring is proportional to the mass of the ball.
(2)The compression of the spring is independent of the height h.
(3)The gravitational potential energy lost by the ball is equal to the strain energy stored in the spring.

Homework Equations


The Attempt at a Solution


The question state that the contact surface is smooth so energy cannot lose because of friction.So why the the ball eventually stop as the energy in the system is conserve?
And I would like to know why (2) is correct.The value of h determine the gravitational potential energy before releasing the ball,so the maximum potential energy stored in the spring depends on h.
 

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Some of the energy is dissipated inside the spring, because of internal friction. As the spring compresses and releases, its particles move with respect to each other and their motion transforms to internal energy (heat).

ehild
 
ehild said:
Some of the energy is dissipated inside the spring, because of internal friction. As the spring compresses and releases, its particles move with respect to each other and their motion transforms to internal energy (heat).

ehild

Thanks.
And I would like to ask why the compression of the spring is independent of the height h.
As 1/2kx2=mgh,the compression of the spring depends on h.
 
But energy is lost. The ball is in rest on the top of the spring, in equilibrium, and it "forgot" from what height it had fallen down initially. The opposite forces, gravity and spring force balance each other: mg=kx.

ehild
 
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