# Tag Info

### How does this tensegrity table work?

This table works very simply once you see or know it: The white band in the middle supports the upper part against gravity. The metal chains make it so the upper part does not fall over. If you were ...
• 2,758

### How does this tensegrity table work?

Less scientifically speaking, the chains prevent the upper piece from going higher up than their length (they resist the whole structure "stretching"), but do nothing against it falling ...
• 311
Accepted

### In a magnetic field, does the force act on the midpoint of the current carrying wire?

Believe it may just be a convenient approximation since the force is actually distributed along the entire length of the wire, which would be harder to represent in an FBD. When they say forces F1 and ...
• 165

### What's the need for 2 separate laws of motion when the first law is an special case of the second one?

The present point of view is that the first Newton's law establishes a special set of reference frames (the inertial reference frames) where the movement of a body non-interacting with other bodies is ...

### What's the need for 2 separate laws of motion when the first law is an special case of the second one?

There is a consideration that in Newton's time would not have made a difference, but nowadays it does. What if space and time are not Euclidean? What if we would live in a universe with circumstances ...
• 21.2k
Accepted

### Philosophical Discussion of Newton's Second Law

I'll try to write a short answer, focusing directly on your main question that I recast in the correct form as How does one conclude that releasing a block twice as massive from the same position ...

### What's the need for 2 separate laws of motion when the first law is an special case of the second one?

When you apply the second law, 𝐹=𝑚𝑎 with zero force (𝐹 = 0), it shows that acceleration (𝑎) is also zero, which is exactly what the first law states: an object will not change its motion unless a ...

### $a=F/m$ is it possible?

Yes, we say forces cause acceleration, but from the effect (acceleration) we can reason back to the cause. You are right that the equality sign masks the relation of cause and effect, but that is just ...
1 vote

### How is the expression for work in this problem derived?

System: collar. External forces acting on the system: Gravitation force $mg$ acting vertically downwards; Normal force $N$; String-exerted force of $40\,\rm N$. Work done on the system: By the ...
• 97.3k
1 vote
Accepted

### How is the expression for work in this problem derived?

When doing work calculations, we only care about the component of motion in the direction of the force. In this case, we care about how much the distance towards the pulleys changes, since that is the ...
1 vote

### In a magnetic field, does the force act on the midpoint of the current carrying wire?

The key concept and word here is equipollent. Two systems of forces are "equipollent" if they have the same total force and same moments about any point. The magentic force taken to act at ...
• 53.9k
1 vote

### How does this tensegrity table work?

Others have given more scientific answers, but to me its principle becomes obvious when I picture what happens if you remove the rubber band and squeeze the hook parts together using your thumb and ...
• 111
1 vote

### How does this tensegrity table work?

We know that chains and elastic bands can support tension forces, but are useless against compression forces. The wooden parts on the other hand can be considered as a rigid structure. The key ...
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1 vote

### Philosophical Discussion of Newton's Second Law

Newton's original philosophy is not particularly relevant to modern physics. He had the first word on the theory that bears his name, not the last word. There is no need and no particular benefit to ...
• 102k
1 vote

### Does force cause acceleration or acceleration cause force?

Former philosophy student, current physics student here. This question is perfect since it pertains to the mathematical principles of natural philosophy. I can answer your question directly: it is ...

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