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oksian1 [2.3K]
3 years ago
9

A simple machine has efficiency 90%. What does it mean? No machine has 109 efficiency,why?​

Physics
2 answers:
Marrrta [24]3 years ago
7 0

Answer:

<em>Efficiency of a machine is 90% this means that the total energy produced to the machine only 90% is useful and given as a output.</em>

<em>Machines are not 100% efficient because some of the work done by a machine is used to overcome friction</em>

Novay_Z [31]3 years ago
7 0

Explanation:

A simple machine has efficiency 90% means that 10% of the applied effort is wasted due to overcoming friction and 90% of the applied force is used in doing useful work .No machinr has hundred percent efficiency because every machine is affected by overcoming friction .

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Which statement is true about effective nuclear charge?a. Effective nuclear charge decreases as we move to the right across a ro
MissTica

Answer:

Option b. Effective nuclear charge increases as we move to the right across a row in the periodic table

Explanation:

The <em>effective nuclear charge </em>is a measure of how strong the protons in the nucleus of an atom attract the outermost electrons of such atom.

The <em>effective nuclear charge</em> is the net positive charge experienced by valence electrons and is calculated (as an approximation) by the equation: Zeff = Z – S, where Z is the atomic number and S is the number of shielding electrons.

The shielding electrons are those electrons in between the interesting electrons and the nucleus of the atom.

Since the shielding electrons are closer to the nucleus, they repel the outermost electrons and so cancel some of the attraction exerted by the positive charge of the nucleus, meaning that the outermost electrons feel less the efect of attraction of the protons. That is why in the equation of Zeff, the shielding electrons (S) subtract the total from the atomic number Z.

The <em>effective nuclear charge</em>, then, is responsible for some properties and trends in the periodic table. Here, you can see how this explains the trend of the atomic radius (size of the atom) accross a row in the periodic table.

  • As the<em> effective nuclear charge</em> is larger, in a same row of the periodic table, the shielding effect is lower, the outermost electrons are more strongly attracted by the nucleus, and the size of the atoms decrease. That is why as we move to the right in the periodic table, the size of the atoms decrease.

3 0
3 years ago
Two friends are playing a version of proton golf where the hole is marked by a single proton. The first friend reads his meter,
yarga [219]

Answer:

the electric field strength on the second one is 2.67 N/C.

Explanation:

the electric fiel on the first one is:

E1 = k×q/(r^2)

r^2 = k×q/(E1)

     = (9×10^9)×(q)/(24.0)

     = 375000000q

then the electric field on the second one is:

E2 = k×q/(R^2)

we know that R = 3r

                       R^2 = 9×r^2

E2 = k×q/(9×r^2)

     = k×q/(9×375000000q)

     = k/(9×375000000)

     = (9×10^9)/(9×375000000)

     = 2.67 N/C

Therefore, the electric field strength on the second one is 2.67 N/C.

5 0
3 years ago
Suppose that, while lying on a beach near the equator watching the Sun set over a calm ocean, you start a stopwatch just as the
Yuri [45]

Ans:  Let d is the distance from height to our eyes.

<span>Applying the Pythagoras theorem, we  get,</span>

<span>Check image: </span>

7 0
3 years ago
How do we know that solar system formed from a spinning disk of gas and dust
Mademuasel [1]

The evidence of this research is published in the scientific journal Nature communication.

<u>Explanation:</u>

Our solar system shaped about 4.5 billion years prior from a thick haze of interstellar gas and residue. The cloud crumbled, potentially due to the shock wave of a close by detonating star, called a supernova. At the point when this residue cloud crumbled, it framed a sun powered cloud—a turning, whirling plate of material.

The research is distributed in the latest issue of journal Nature Communications. About 4.6 billion years prior, a haze of gas and residue that in the end framed our nearby planetary group was upset. The following gravitational breakdown framed the proto-Sun with an encompassing plate where the planets were conceived.

5 0
3 years ago
When the mass of an object decreases, the force of gravity
Viktor [21]
Hello There!

From what i know, gravitational force increases if the mass is increased.
If the mass is being decreased, then i assume it will be B. Decreases.

Hope This Helps You!
Good Luck :) 

- Hannah ❤
8 0
3 years ago
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