1. 1. One end of a massless spring is attached to a vertical wall and the other end is attached to a block of mass m=2.0 Kg on a frictionless horizontal surface(see the following figure). The spring has a spring constant k=6.0 N/m. At some instant the spring is stretched from its relaxed position by 3.0 m and the block is moving to the right at a speed of 8.0 m/s. (a) What is the velocity of the block when the spring is stretched by 4.0 m? (b) How much distance is the spring stretched or compressed from its relaxed position when the block is moving to the right at a speed of 5.0 m/s.

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2. Referring to the above figure, one end of a massless spring is attached to a vertical wall and the other end is attached to a block of mass 2.0 Kg on a frictionless horizontal surface. Initially the spring is at its relaxed position and the block is stationary. Then a constant force F pulls the block horizontally to the right. When the spring is stretched by 1.0 m, the block reaches a maximal kinetic energy of 4.0 J. The block stops when the spring is stretched by 2.0 m. Please find the spring constant k and the magnitude of the horizontal component of force F .

2. Originally Posted by andylau9077
1. One end of a massless spring is attached to a vertical wall and the other end is attached to a block of mass m=2.0 Kg on a frictionless horizontal surface(see the following figure). The spring has a spring constant k=6.0 N/m. At some instant the spring is stretched from its relaxed position by 3.0 m and the block is moving to the right at a speed of 8.0 m/s. (a) What is the velocity of the block when the spring is stretched by 4.0 m? (b) How much distance is the spring stretched or compressed from its relaxed position when the block is moving to the right at a speed of 5.0 m/s.

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|__/\/\/\/\/\/\/\___|.........|
|______________|____|____

2. Referring to the above figure, one end of a massless spring is attached to a vertical wall and the other end is attached to a block of mass 2.0 Kg on a frictionless horizontal surface. Initially the spring is at its relaxed position and the block is stationary. Then a constant force F pulls the block horizontally to the right. When the spring is stretched by 1.0 m, the block reaches a maximal kinetic energy of 4.0 J. The block stops when the spring is stretched by 2.0 m. Please find the spring constant k and the magnitude of the horizontal component of force F .

We don't do your homework for you. What have you tried on your own?

3. Ok, really? First the forum introduces negative speed and now massless springs? Where is all this new research coming from and where is any empirical proof of these things? I really am not sure how one would go about attaching something massless to anything either. What would there be to attach?

4. Mayflow, it's an idealised concept, but it doesn't mean that you cannot get quite close to it under certain circumstances.

5. But I don't know how to consider something massless as being a coiled spring. What does it coil? Ok for you Jila. My thoughts have no mass. If I coil them with my massless mind, they gain potential. Therfor with my thoughts I can create Universes! (I may have skipped a step or two) - I have to admit that the idea of masslessness has an appeal to me. I may digress once again into philosophy (if that actually is a digression) - but I think it should be ok since we are speaking of massless springs and negative speeds. I really never think I will be able to divorce my love of the mind from physics and science.

6. You don't have to. Just think of it as being an idealised spring. Perfectly springlike but weighing nothing. It can never be realised, but you can get close. These idealisations are important so we can make complicated situations less complicatd and see the wood for the trees, so to speak.

7. You probably mean to see the trees for the forest, which is to see the individual mindsets rather than the bigger picture? This can get tricky.

8. Where I live (UK) the saying is "the wood from the trees" but I think it has the same meaning. It doesn't have to do with mindsets. It's just about removing the noise and getting to the crux of the matter.

9. Originally Posted by Jilan
Where I live (UK) the saying is "the wood from the trees" but I think it has the same meaning. It doesn't have to do with mindsets. It's just about removing the noise and getting to the crux of the matter.
I think I see. Creating a better signal to noise ratio. Minds tend to be awefully noisy though. Another thing is that how would we mutually all agree what the "crux" of the matter should be? I don't even have any idea of what mine would be, much less that of the others here.

Do you have an idea of how to get to the crux of whatever the matter may be?

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