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slava [35]
3 years ago
14

Four identical metallic spheres with charges of +8.2 µC, +9.0 µC, −7.8 µC, and −8.8 µC are placed on a piece of paper. The paper

is lifted on all corners so that the spheres come into contact with each other simultaneously. The paper is then flattened so that the metallic spheres become separated.
a. What is the resulting charge on each sphere?
b. How many excess or absent electrons (depending on the sign of your answer to part (a)) correspond to the resulting charge on each sphere?
Physics
1 answer:
tigry1 [53]3 years ago
6 0

Answer:

a) 0.15 μC b) 9.4*10¹¹ electrons.

Explanation:

As the total charge must be conserved, the total charge on the spheres, after being brought to contact each other, and then separated, must be equal to the total charge present in the spheres prior to be put in contact:

Q = +8.2μC +9.0 μC +(-7.8 μC) + (-8.8 μC) = +0.6 μC

As the spheres are assumed perfect conductors, as they are identical, once in contact each other, the excess charge spreads evenly on each sphere, so the final charge, on each of them, is just the fourth part of the total charge:

Qs = Qt/4 = 0.6 μC / 4 = 0.15 μC.

b) As the charge has a positive sign, this means that each sphere has a defect of electrons.

In order to know how many electrons are absent in each sphere, we can divide the total charge by the charge of one electron, which is the elementary charge e, as follows:

N =\frac{0.15e-6C}{1.6e-19C}  = 9.4e11  electrons

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Phoenix [80]

Answer:

34 meters

Explanation:

20 meters +14 meters =34 meters

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3 years ago
A satellite in the shape of a solid sphere of mass 1,900 kg and radius 4.6 m is spinning about an axis through its center of mas
konstantin123 [22]

Answer:

Therefore, the new rotation rate of the satellite is 6.3 rev/s.

Explanation:

The expression for conservation of the angular momentum (L) is

L_{i} = L_{f}  I_{i}\times\omega_{i} = I_{f}\times\omega_{f}

Where

I_{i}\ and \ \omega_{i} initial moment of inertia and angular velocity

I_{f}\ and \ \omega_{f} is the final moment of inertia and angular velocity

The expression of moment of inertia of the satellite (a solid sphere) is

I_{i} = \frac{2}{5}m_{s}r^{2}

Where m_{s} is the satellite mass

r is the  radus of the sphere

Substititute 1900kg for m and 4.6m for r

I_{i} = \frac{2}{5}m_{s}r^{2}\\\\ = \frac{2}{5}\times1900 kg\times (4.6 m)^{2} \\\\= 1.61 \cdot 10^{4} kgm^{2}

The final moment of inertia of the satellite about the centre of mass

I_{f} = I_{i} + 2\timesI_{x} \\\\= 1.61 \cdot 10^{4} kgm^{2} + 2\times\frac{1}{3}m_{x}l^{2}

Where m_{x} is the antenna's mass and

I is the length of the antenna

I_{f} = 1.61 \cdot 10^{4} kgm^{2} + 2\times\frac{1}{3}150.0 kg\times(6.6 m)^{2} \\\\= 2.05 \cdot 10^{4} kgm^{2}

So, the Final rotation rate of the satellite is:

I_{i}\times\omega_{i} = I_{f}\times\omega_{f} \\\\\omega_{f} = \frac{I_{i}\times\omega_{i}}{I_{f}} \\\\= \frac{1.61 \cdot 10^{4} kgm^{2}\times8.0 \frac{rev}{s}}{2.05 \cdot 10^{4} kgm^{2}} \\\\= 6.3 rev/s

Therefore, the new rotation rate of the satellite is 6.3 rev/s.

5 0
4 years ago
An astronaut stands by the rim of a crater on the Moon, where the acceleration of gravity is 1.62 m/s2 and there is no air. To d
Nesterboy [21]

Answer:

12.1 seconds

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity = 0

s = Displacement = 120 m

a = Acceleration due to gravity on Moon = 1.67 m/s²

Equation of motion

v^2-u^2=2as\\\Rightarrow -u^2=2as-v^2\\\Rightarrow -u^2=2\times -1.67\times 120-0^2\\\Rightarrow u=\sqrt{2\times 1.67\times 120}\\\Rightarrow u=20.02\ m/s

v=u+at\\\Rightarrow t=\frac{v-u}{a}\\\Rightarrow t=\frac{0-20.2}{-1.67}\\\Rightarrow t=12.1\ s

Time taken by the rock to hit the bottom of the crater is 12.1 seconds

5 0
4 years ago
In nuclear fission, a nucleus splits roughly in half. (a) What is the potential 2.00 × 10−14 m from a fragment that has 46 proto
Valentin [98]

Answer:

electric potential is 3.31 × 10^{6} V

potential energy is 152 MeV

Explanation:

given data

fragment charge  Q = 46 protons = 46 × 1.6 × 10^{-19} C

to find out

electric potential  and potential energy

solution

we know here distance from fragment d = 2 × 10^{-14} m

and constant for electric force k that is 9 × 10^{9} N-m²/C²

so that we can find electric potential = kQ/d

electric potential = 9 × 10^{9}[/tex ×46 × 1.6 × [tex]10^{-19} / ( 2 × 10^{-14} )

electric potential = 3.31 × 10^{6} V

and

we know relation between electric potential and potential

that is  V = U/q

so U will be = qV

now put all value

we get potential energy U

potential energy = 46 × 3.31 × 10^{6}

potential energy = 1.52 × 10^{8} eV

so potential energy = 152 MeV

4 0
3 years ago
At the point of fission, a nucleus of ^235 U that has 92 protons is divided into two smaller spheres, each of which has 46 proto
IrinaK [193]

Answer : F = 3.5\times10^{3}\ N

Explanation :

Given that

Radius of sphere r = 5.90\times 10^{-15}\ m

The distance between the centers of the two spheres is

r = 2\times 5.90\times 10^{-15}\ m

The charge of the sphere q = 46\times1.6\times10^{-19} C

The magnitude of the repulsive force between the charges pushing them a part is

Using coulomb law

F = \dfrac {kq_{1}q_{2}}{r^{2}}

F = \dfrac{9\times10^{9}\times (46\times1.6\times10^{-19})^{2}C^{2}}{2\times(5.90\times10^{-15})^{2}\ m^{2}}

F = 3501.3\ N

F = 3.5\times10^{3}\ N

Hence, this is the required solution.









3 0
3 years ago
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