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3 years ago

Why does the gravitational force between earth and moon predominate over electrical forces?

Physics

1 answer:

nadezda [96]3 years ago

4 0

Answer:

Because the Earth and the Moon are electrically neutral

Explanation:

The gravitational force between the Earth and the Moon is given by

$F=G\frac{mM}{r^2}$

where G is the gravitational constant, m is the mass of the Moon, M is the mass of the Earth, r is the distance between the Moon and the Earth. Since both the Earth and the Moon have large masses, m and M are big, so the gravitational force between the two objects is large.

On the contrary, the electrostatic force between the Earth and the Moon is given by

$F=k\frac{q_1 q_2}{r^2}$

where k is the Coulomb's constant, q1 is the charge of the Moon, q2 is the charge of the Earth, r is the distance between the Moon and the Earth. However, big objects (and planets as well) are electrically neutral, which means that they have zero charge (because if they had charge, they would tend to attract charge of the opposite sign, becoming neutral again). Therefore, the values of q1 and q2 are approximately zero, so the electrostatic force is zero as well.

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A ball that rolls on the ground is initially propelled with a speed of 45 km / h and after 10 seconds it stops. Assuming you los

solmaris [256]

Answer:

a) -1.25 m/s²

b) 62.5 m

Explanation:

Convert km/h to m/s:

45 km/h × (1000 m/km) × (1 h / 3600 s) = 12.5 m/s

a = Δv / Δt

a = (0 m/s − 12.5 m/s) / 10 s

a = -1.25 m/s²

Δx = ½ (v + v₀) t

Δx = ½ (0 m/s + 12.5 m/s) (10 s)

Δx = 62.5 m

5 0

3 years ago

A 3.2 kg particle starts from rest at x = 0 and moves under the influence of a single force Fx = 4 + 15.7 x − 1.5 x 2 , where Fx

garik1379 [7]

Answer:

Explanation:

Work: This can be defined as the product of force and distance. The unit of work is Joules (J). it can be expressed mathematically as

W = F×d

W = $\int\limits^b_a {Fx} \, dx$ .................................. Equation 1

Where b = upper limit, a = lower limit, Fx = expression of force.

Given: a = 0 , b = 1.3 m, Fx = 4 + 15.7x - 1.5x²

Substituting these values into equation 1

W = $\int\limits^a_b {(4 + 15.7x - 1.5x^{2} )dx} \,$

W = ᵇ[4x + 15.7x²/2-1.5x³/3 +C]ₐ

Work = upper limit - lower limit

Work = ᵃ[4x + 15.7x²/2 - 1.5x³/3 +C] - [4x + 15.7x²/2 + 1.5x³/3 +C]ᵇ............... Equation 2

Substituting the values of a and b into equation 2

Work = [4(1.3) + 15.7(1.3)²/2-1.5(1.3)³/3 + C] - [0 +C]

Work = [5.2 + 26.53 -3.29 + C] - C

Work = 28.44 J

Work done by the force = 28.44 J.

8 0

3 years ago

A strong lightning bolt transfers an electric charge of about 31 C to Earth (or vice versa). How many electrons are transferred?

olchik [2.2K]

Answer:

$m=5.78\times 10^{-3}\ g$

$n_e=1.935\times 10^{20}$ is the no. of electrons

Explanation:

Given:

quantity of charge transferred, $Q=31\ C$

No. of electrons in the given amount of charge:

As we have charge on one electron $1.602\times 10^{-19}\ C$

so,

$n_e=\frac{Q}{e}$

$n_e=\frac{31}{1.602\times 10^{-19}}$

$n_e=1.935\times 10^{20}$ is the no. of electrons

Now if each water molecules donates one electron:

Then we require $n=1.935\times 10^{20}$ molecules.

Now the no. of moles in this many molecules:

$n_m=\frac{n}{N_A}$

where

$N_A=6.022\times 10^{23}$ Avogadro No.

$n_m=\frac{1.935\times 10^{20}}{6.022\times 10^{23}}$

$n_m=3.213\times 10^{-4}\ moles$

We have molecular mass of water as M=18 g/mol.

So, the mass of water in the obtained moles:

$n_m=\frac{m}{M}$

where:

m = mass in gram

$3.213\times 10^{-4}=\frac{m}{18}$

$m=5.78\times 10^{-3}\ g$

7 0

3 years ago

Barry is conducting an experiment and rolls a tennis ball down a ramp. Which best describes the motion of the tennis ball? It do

yawa3891 [41]

Answer:

A. It does not exhibit projectile motion and follows a straight path down the ramp.

7 0

3 years ago

Read 2 more answers

Direct tension indicators are sometimes used instead of torque wrenches to ensure that a bolt has a prescribed tension when used

natali 33 [55]

Complete Question

The complete question is shown on the uploaded image

Answer:

The tension on the shank is $T =8391.6 N$

Explanation:

From the question we are told that

The strain on the strain on the head is $\Delta l = 0.1 mm/mm = \frac{0.1}{1000} = 0.1 *10^{-3} m/m$

The contact area is $A = 2.8 mm^2 = 2.8* (\frac{1}{1000} )^2 = 2.8*10^{-6} m^2$

Looking at the first diagram

At 600 MPa of stress

The strain is $0.3mm/mm$

At 450 MPa of stress

The strain is $0.0015 mm/mm$

To find the stress at $\Delta l$ we use the interpolation method

$\frac{\sigma_{\Delta l} - \sigma_{0.0015} }{ \sigma _ {0.3} - \sigma_{0.0015} } = \frac{e_{\Delta l } - e_{0.0015}}{e_{0.3} - e_{ 0.0015}}$

Substituting values

$\frac{\sigma _{\Delta l} - 450}{600 - 450} = \frac{0.1 -0.0015}{0.3 - 0.0015}$

$\sigma _{\Delta l} -450 = 49.50$

$\sigma _{\Delta l} = 499.50 MPa$

Generally the force on each head is mathematically represented as

$F = \sigma_{\Delta l} * A$

Substituting values

$F = 499.50*10^{6} * 2.8*10^{-6}$

$=1398.6N$

Now the tension on the bolt shank is as a result of the force on the 6 head which is mathematically evaluated as

$T = 6 * F$

$= 6* 1398.6$

$T =8391.6 N$

6 0

3 years ago