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3 years ago

Does the nucleus of an atom have a positive or negative charge?

2 answers:

8 0

A.
because the nucleus contains protons and neutrons BUT neutrons are neutral and protons are positive, so the answer is A

Marta_Voda [28]3 years ago

7 0

Answer:

A. The nucleus contain protons, so it has a positive charge.

Explanation:

Nucleus is the dense core of an atom which contains protons and neutrons.

Protons have positive charge.

Neutrons have no charge.

Electrons are negatively charged.

But electrons are present in the energy level i.e. outside nucleus, that is why a nucleus contains positive charge.

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A robotic rover on Mars finds a spherical rock with a diameter of 10 centimeters [cm]. The rover picks up the rock and lifts it

Makovka662 [10]

Answer: 5166.347

Explanation:

The specific gravity of a solid $SG$ (also called relative density) is the ratio of the density of that solid $\rho_{rock}$ to the density of water $\rho_{water}=1 kg/m^{3}$ (normally at $4\°C$ ):

$SG=\frac{\rho_{rock}}{\rho_{water}}$ (1)

On the other hand, the density of the rock is calculated by:

$\rho_{rock}=\frac{m_{rock}}{V_{rock}}$ (2)

Where:

$m_{rock}$ is the mass of the rock

$V_{rock}=\frac{4}{3} \pi r^{3}$ is the volume of the rock, since is spherical

Well, we already know the value of $\rho_{water}$ , but we need to find $\rho_{rock}$ in order to find the rock's specific gravity; and in order to do this, we firsly have to find $m_{rock}$ and then calculate $V_{rock}$ :

In the case of the mass of the rock, we can calclate it by the following equation:

$W_{rock}=m_{rock}g_{mars}$ (3)

Where:

$W_{rock}$ is the weight if the rock in mars

$g_{mars}=3.7 m/s^{2}$ is the acceleration due gravity in Mars

Isolating $m_{rock}$ :

$m_{rock}=\frac{W_{rock}}{g_{mars}}$ (4)

$m_{rock}=\frac{W_{rock}}{3.7 m/s^{2}}$ (5)

To find $W_{rock}$ we can use the following equation of the potential gravitational energy $U$ :

$U=W_{rock}H$ (6)

Where:

$U=2 J=2 Nm$ is the potential energy

$H=20 cm \frac{1m}{100 cm}=0.2 m$ is the height at which the rock has the mentioned potential energy

Isolating $W_{rock}$ :

$W_{rock}=\frac{U}{H}$ (7)

$W_{rock}=\frac{2 Nm}{0.2 m}$ (8)

$W_{rock}=10 N$ (9)

Substituting (9) in (5):

$m_{rock}=\frac{10 N}{3.7 m/s^{2}}$ (10)

$m_{rock}=2.702 kg$ (11)

Substituting (11) in (2):

$\rho_{rock}=\frac{2.702 kg}{V_{rock}}$ (12) At this point we only need to find the volume of the rock, knowing its diameter is $d=10 cm$ , hence its radius is $r=\frac{d}{2}=5 cm$

$V_{rock}=\frac{4}{3} \pi (5 cm)^{3}$ (13)

$V_{rock}=523.59 cm^{3} \frac{1 m^{3}}{(100 cm)^{3}}=0.000523 m^{3}$ (14)

Substituting (14) in (12):

$\rho_{rock}=\frac{2.702 kg}{0.000523 m^{3}}$ (15)

$\rho_{rock}=5166.34 kg/m^{3}$ (16)

Substituting (16) in (1):

$SG=\frac{5166.34 kg/m^{3}}{1 kg/m^{3}}$ (17)

Finally we obtain the specific gravity of the rock:

$SG=5166.347$

7 0

3 years ago

Why is alternating current more effective at long–distance travel than direct current?

amid [387]

Because we can send high voltage, low current which is more efficient since large amounts of current in the line causes power inefficiencies. AC can be transformed locally to high current lower voltage

6 0

3 years ago

Read 2 more answers

Would the springs inside a bathroom scale be more compressed or less compressed if you weighed yourself in an elevator that was

Ber [7]

More compressed. moving up = apparent weight (i.e., your norma force) is greater. this means you’ll weighr more and push those springs down even more than you would at rest.

6 0

3 years ago

Which part of the female reproductive system produces ova?

vovangra [49]

A would be the best answer beacuse
Ovaries - small, oval-shaped glands that are located on either side of the uterus. The ovaries produce eggs (ova - an ovum is one egg, ova means multiple eggs.) The ovaries also produce the main female sex hormones which are released into the bloodstream.

5 0

3 years ago

Read 2 more answers

Which property of sound waves decreases as the square of the distance from the source increases?

Vitek1552 [10]

Answer:

Intensity

Explanation:

The intensity of a sound wave is equal to the ratio between to the power emitted by the source divided by the area of the spherical surface through which the wave propagates:

$I=\frac{P}{4\pi r^2}$

where

P is the power

$4\pi r^2$ is the area of the spherical surface

r is the distance from the source

As we see from the formula, the intensity is inversely proportional to the square of the distance from the source:

$I\propto \frac{1}{r^2}$

so, intensity is the correct answer.

3 0

3 years ago