# Questions tagged [length]

The tag has no usage guidance.

42 questions
Filter by
Sorted by
Tagged with
28 views

### What effect does diameter and length of a wire have on the force and extension? [closed]

For example, if wire $A$ has diameter $D$ and length $L$ when a force of $4N$ is applied, it extends to let's say, $0.8mm$. Another wire $B$ has length and diameter $2L$ and $2D$ respectively. Now, ...
47 views

### Length measure in Astronomy

In cosmology, we have a couple of different length measures. Among them, comoving and proper distnlances seem to be good fit to real world use cases in astronomy. So my quesion is which length measure ...
9 views

### Main scale reading and pitch of micrometer or a screw gauge

In a micrometer should the value of one main scale division be equal to the pitch? The measurements of the micrometer depend on the number on rotations and hence each rotation should be factored in. ...
93 views

### Why torque increases with arm length when same force is applied?

Just want to know why the door turns less (less torque) at the point closer to the hinge (point A) than at the outer point at the handle (point B) when the same force is applied. If same force is not ...
73 views

### Why is the symmetry of measurements in SR no longer valid in GR?

In special relativity, we know that if an inertial observer $A$, having a relative motion WRT an inertial observer $B$, attributes, say, time dilation and length contraction to respectively $B$'s ...
48 views

### Can we measure macroscopic objects with width atom precision?

Can we measure a length of a macroscopic object, like the length of an edge a piece of steel, with atomic level precision, in the sense that we could measure the length of the edge of a crystal ...
43 views

### Uncertainty in length measurement

I am trying to measure the length and the uncertainty in length of a fiber optic cable for measuring the speed of light. So far, I have measured it the standard way: Using a standard meter scale. I ...
209 views

### Focal length for thick lens [closed]

How can I find the focal length of a thick lens by the method of ray tracing ? I know the ray matrix method but by ray tracing I don't get to an answer.
47 views

### Is cross-sectional area over length classified separately from length?

The ratio of cross-sectional area to length (or its reciprocal) appears in several formulas, including those for electrical resistance and capacitance in terms of the resistivity and permittivity. ...
446 views

### How length is an invariant in Euclidean space?

The special theory of relativity shows that intervals are invariant under Lorentz transform in the Minkowski space -time. But how can we prove (any postulates or theory) that the length is an ...
66 views

### The length of a string attached to a wall?

I feel really dumb for asking this question. I apologize in advance. When the example of a string attached to a wall is given to explain waves and the ressonance frequencies, the length of the string ...
618 views

### Is length an extensive property?

From my experience, volume, surface and length are extensive properties. Indeed : the reunion of two cubes of 1 $m^3$ leads to a cube of 2 $m^3$ the reunion of two tiles of 1 $m^2$ leads to a tile ...
394 views

### Profile of a platinum-iridium meter bar

The former meter standard, platinum-iridium meter bar, had a specific cross section somewhat resembling mixed variant of letters "X" and "H" with serifs (Image source): What was the reasoning behind ...
61 views