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4 years ago

Caves are formed from:

2 answers:

6 0

Caves are formed by the dissolution of limestone. Rainwater picks up carbon dioxide from the air and as it percolates through the soil, which turns into a weak acid. This slowly dissolves out the limestone along the joints, bedding planes and fractures, some of which become enlarged enough to form caves

Furkat [3]4 years ago

3 0

Answer:

The correct answer is limestone.

Explanation:

A cave is the product of undone limestone.

This stone is weakened by the rain and carbon dioxide that is absorbed by the soil, this causes the stone to fracture, sometimes enough to form a cave.

Where there is more water flow, the bigger the cave will be.

What is necessary for a cave to form is a stone that can be diluted with water.

Because of gravity, water will always want to go down, this is what will cause the rock to dissolve forming different types of caves.

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43. The particle consists of fast moving electrons is.

marishachu [46]

Answer:

Explanation: someone help me please you want free points right

8 0

3 years ago

When a metal rod is heated, its resistance changes both because of a change in resistivity and because of a change in the length

monitta

Answer:

$3.34\Omega$

Explanation:

The resistance of a metal rod is given by

$R=\frac{\rho L}{A}$

where

$\rho$ is the resistivity

L is the length of the rod

A is the cross-sectional area

The resistivity changes with the temperature as:

$\rho(T)=\rho_0 (1+\alpha (T-T_0))$

where in this case:

$\rho_0$ is the resistivity of silver at $T_0=21.0^{\circ}C$

$\alpha=6.1\cdot 10^{-3} ^{\circ}C^{-1}$ is the temperature coefficient for silver

$T=180.0^{\circ}C$ is the current temperature

Substituting,

$\rho(180^{\circ}C)=\rho_0 (1+6.1\cdot 10^{-3}(180-21))=1.970\rho_0$

The length of the rod changes as

$L(T)=L_0 (1+\alpha_L(T-T_0))$

where:

$L_0$ is the initial length at $21.0^{\circ}C$

$\alpha_L = 18\cdot 10^{-6} ^{\circ}C^{-1}$ is the coefficient of linear expansion

Substituting,

$L(180^{\circ}C)=L_0(1+18\cdot 10^{-6}(180-21))=1.00286L_0$

The cross-sectional area of the rod changes as

$A(T)=A_0(1+2\alpha_L(T-T_0))$

So, substituting,

$A(180^{\circ}C)=A_0(1+2\cdot 18\cdot 10^{-6}(180-21))=1.00572A_0$

Therefore, if the initial resistance at 21.0°C is

$R_0 = \frac{\rho_0 L_0}{A_0}=1.70\Omega$

Then the resistance at 180.0°C is:

$R(180^{\circ}C)=\frac{\rho(180)L(180)}{A(180)}=\frac{(1.970\rho_0)(1.00285L_0)}{1.00572A_0}=1.9644\frac{\rho_0 L_0}{A_0}=1.9644 R_0=\\=(1.9644)(1.70\Omega)=3.34\Omega$

7 0

3 years ago

If a liter of water is heated from 20c to 50c what happens to its colume

Aleksandr-060686 [28]

The volume of the water would increase as it is heated.

3 0

3 years ago

Tycho Brahe built the first what?

wlad13 [49]

Answer:

Brahe showed irregularities in the Moon's orbit and discovered a new star in the Cassiopeia formation. Brahe invented many instruments such as the Tyconian Quadrant which were widely copied and led to the invention of improved observational equipment. In 1600, Tyco Brahe hired Johannes Kepler as his assistant.

Explanation:

https://www.google.com/search?q=Tycho+Brahe+built+the+first+what%3F&rlz=1C1CHBF_enUS880US880&oq=Tycho+Brahe+built+the+first+what%3F&aqs=chrome..69i57j69i61.1130j0j7&sourceid=chrome&ie=UTF-8

6 0

3 years ago

The heart rate that indicates your fitness level is the

MrRa [10]

The heart rate that indicates your fitness level is the Resting Heart Rate.

<u>Explanation:</u>

The statement from Welch says that when we practise more and do an exercise harder, then the heart rate at rest would be low. This is the main reason for considering resting heart rates as a good indicator to one’s fitness level. The normal adult heart rate at rest is 60 to 100 bpm (beat per minute).

In general, a lower heart rate means a calmer heart rate and good heart health. For example, for a well-trained athlete, a normal heart rate can be closer to 40 bpm. Our resting rhythm, the measure of how often the heart beats every minute at rest.

8 0

4 years ago