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olasank [31]
3 years ago
11

Find the approximate kinetic energy of a circular wheel of radius r and mass M that is rotating about its center at 2 cycles/s.

Assume the wheel’s mass is concentrated at the rim and the mass of the wheel’s spokes is negligible.
Physics
1 answer:
alukav5142 [94]3 years ago
6 0

Answer:

8M(r\pi)^2

Explanation:

First we convert 2 cycles/s to angular velocity knowing that each circle has an angle of 2π

\omega = 2 * 2\pi = 4\pi rad/s

Then we calculate the moment of inertia of the cylindrical shell, assuming there's no mass inside the wheel (only at the rim):

I = mr^2 = Mr^2

So the kinetic energy of this is

E_k = I\omega^2/2 = Mr^2*(4\pi)^2/2 = 8M(r\pi)^2

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What information did the movement of the bubble over a specified distance in the calibrated respirometer provide
emmasim [6.3K]

Answer:

The following explanatory section gives an explanation of this question.

Explanation:

  • This means that perhaps the bubble moves more than a certain duration throughout the calibration breath meter offers the rate as well as oxygenation consumed inside this cell.
  • Inside that respirometer, oscillation of something like the bubble gave a technique of multiplying the quantity of oxygenation that is used by the seedlings mostly through cell membrane breathing.
3 0
3 years ago
Pressure is about 1000 hPa at sea level and about 500 hPa at an altitude of 5.5 km. Why doesn’t this vertical pressure gradient
saul85 [17]

Answer:

A. The upward pressure gradient force is balanced by gravity.

Explanation:

A. is correct because the pressure difference is actually generated by gravity. As in the following formula for the pressure at different points:

p = p_0 + \rho g h

where p, p_0 are the pressure at 2 points, ρ is the density of the fluid, g is the gravitational constant, and h is the height difference.

B is incorrect because friction in air is too small to make an effect.

C is incorrect because the Coriolis force is horizontal, not vertical.

D is incorrect because a difference of 500 hPa = 50000 Pa, this is half of the atmospheric pressure.

E is incorrect because temperature cannot generate force.

6 0
3 years ago
Hello....I need help with this question.
musickatia [10]

Answer:

3.2 m/s²

Explanation:

Acceleration can be calculated as:

v = u + at (where v is final velocity, u is initial velocity, a is acceleration and t is time)

25 m/s  = 9 m/s  + a(5 s)  (a is unknown)

16 m/s  = a(5 s)

a = 3.2 m/s²

We assume that this is a uniform acceleration (meaning that the velocity increases at an equal rate for those 5 seconds).

6 0
3 years ago
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Plzzzz help it for civics
Viktor [21]

Answer:

A : the colonists dumped tea in Boston Harbor

6 0
3 years ago
Which scientist was the first to conclude through experimentation that atoms have positive charges in their nuclei?
Pavel [41]
<h2>Answer: Ernest Rutherford </h2>

Ernest Rutherford was a British physicist and chemist of New Zealand origin, who conducted a series of experiments together with Hans Geiger and Ernest Marsden; where the result led him to propose a new atomic model.

It should be noted that at that time, the "accepted" atomic model was Thomson's raisin pudding atomic model<u> </u><em><u>(electrons with negative charge immersed an the atom of positive charge that counteracted the negative charge of the electrons, like raisings embedded in a pudding)</u></em>, who discovered the electron and formerly was a professor of Rutherford.  

Now, the experiment conducted under the direction of Ruherford at the laboratories of the University of Manchester during the year 1911; was for the purpose of <u>corroborating Thomson's atomic model</u>. To achieve this, a thin metal sheet was bombarded with alpha particles (nuclei of helium gas).

The idea was that these alpha particles, having positive electric charge, were attracted by the atom's negative charges and repelled by the positive charges, and it was expected that they would pass through the thin sheet without hardly deviating. Then, to observe the crash site of the particle, a phosphorescent screen was placed behind and on the sides of the metal sheet.

For according to Thomson's atomic model the positive and negative charges were evenly distributed, the sphere (the atom) had to be electrically neutral, and <u>the alpha particles would pass through the sheet without deviating. </u>

However, the results were surprising:

As expected, most of the particles went through the sheet without deviating.

<h2>But some suffered large deviations and, most importantly, <u>a small number of particles bounced backwards</u>. </h2>

That is:

<h2>The alpha particle beam was scattered (repelled) when it hit the thin metal sheet. </h2>

These facts could not be explained by Thomson's atomic model, so Rutherford developed another, suggesting that:

<h2><em>There is a concentration of charge in the center of the atom (which was later called nucleus) surrounded by electrons. </em></h2>

This new model could explain the proven fact in his experiments that some particles bounced in the direction opposite to the incident particles, because the electrical charge of this nucleus was positive, equal to the electrical charge of the alpha particles.

This is how Rutherford proposed a new atomic model and discovered the existence of the nucleus. However, this was not the definitive model, because on 1913 it was replaced by Bohr's.

8 0
3 years ago
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