(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

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A block of mass m = 3.5 kg rests on a frictionless floor. It is attached to a spring with a relaxed length L = 5 m. The spring has spring constant k = 12 N/m and is relaxed when hanging in the vertical position. The block is pulled d = 4 m to one side. In this problem, the block is always constrained to move on the floor (i.e. it never leaves the floor).

By what amount is the spring extended?

I found this to be 1.403 m.

What is the potential energy stored in the spring?

I found this to be 11.8125 J.

The block is released but is constrained to move horizontally on the frictionless floor. What is the maximum speed it attains?

I found this value to be 2.598 m/s.

Let's change the problem a bit. When the spring is vertical (hence, unstretched), the block is given an initial speed equal to 1.4 times the speed found in the last part.

How far from the initial point does the block go along the floor before stopping?

I found this to be 4.848 m.

What is the magnitude of the acceleration of the block at this point (when the spring is stretched farthest)?

This is the last part I cannot figure out.

2. Relevant equations

3. The attempt at a solution

I tried taking the KE (23.1526) that I found and tried to divide it by the distance (4.848m) (W=Fxd). And then I divided this force by the mass thinking it would give me the acceleration, and that did not work. I do not know what to do now. =/

Any help would be very much appreciated. thanks. :)

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# Homework Help: Work & Energy (Spring and moving mass)

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