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3 years ago

How do scientists determine motion of objects in the universe??

2 answers:

5 0

Usually, Scientists use "Parallax Method" in order to determine the different positions of an object

Hope this helps!

DerKrebs [107]3 years ago

3 0

Answer: By Doppler effect

Explanation:

The spectrum of the objects in the universe such as stars and galaxies is taken and studied. The apparent change in the frequency/wavelength of the light suggests the motion of these objects.

If the apparent frequency is greater, the light would be blue -shifted which means it is moving towards Earth and if it is red shifted, it would be moving away from the earth. This is apparent change in observed frequency is known as Doppler's effect which studied to determine the motion of objects in the universe.

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Should I apply for the Trusted Helpers Program? I want a real answer, if you don’t understand it don’t answer.

Svetradugi [14.3K]

Yes you should if you will like to. It is your opinion so follow your dreams if they are your dreams.

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3 years ago

Read 2 more answers

A thin spherical spherical shell of radius R which carried a uniform surface charge density σ. Write an expression for the volum

ozzi

Answer:

Explanation:

From the given information:

We know that the thin spherical shell is on a uniform surface which implies that both the inside and outside the charge of the sphere are equal, Then

The volume charge distribution relates to the radial direction at r = R

∴

$\rho (r) \ \alpha \ \delta (r -R)$

$\rho (r) = k \ \delta (r -R) \ \ at \ \ (r = R)$

$\rho (r) = 0\ \ since \ r< R \ \ or \ \ r>R---- (1)$

To find the constant k, we examine the total charge Q which is:

$Q = \int \rho (r) \ dV = \int \sigma \times dA$

$Q = \int \rho (r) \ dV = \sigma \times4 \pi R^2$

∴

$\int ^{2 \pi}_{0} \int ^{\pi}_{0} \int ^{R}_{0} \rho (r) r^2sin \theta \ dr \ d\theta \ d\phi = \sigma \times 4 \pi R^2$

$\int^{2 \pi}_{0} d \phi* \int ^{\pi}_{0} \ sin \theta d \theta * \int ^{R}_{0} k \delta (r -R) * r^2dr = \sigma \times 4 \pi R^2$

$(2 \pi)(2) * \int ^{R}_{0} k \delta (r -R) * r^2dr = \sigma \times 4 \pi R^2$

Thus;

$k * 4 \pi \int ^{R}_{0} \delta (r -R) * r^2dr = \sigma \times R^2$

$k * \int ^{R}_{0} \delta (r -R) r^2dr = \sigma \times R^2$

$k * R^2= \sigma \times R^2$

$k = R^2 --- (2)$

Hence, from equation (1), if k = $\sigma$

$\mathbf{\rho (r) = \delta* \delta (r -R) \ \ at \ \ (r=R)}$

$\mathbf{\rho (r) =0 \ \ at \ \ rR}$

To verify the units:

$\mathbf{\rho (r) =\sigma \ * \ \delta (r-R)}$

↓ ↓ ↓

c/m³ c/m³ × 1/m

Thus, the units are verified.

The integrated charge Q

$Q = \int \rho (r) \ dV \\ \\ Q = \int ^{2 \ \pi}_{0} \int ^{\pi}_{0} \int ^R_0 \rho (r) \ \ r^2 \ \ sin \theta \ dr \ d\theta \ d \phi \\ \\ Q = \int ^{2 \pi}_{0} \ d \phi \int ^{\pi}_{0} \ sin \theta \int ^R_{0} \rho (r) r^2 \ dr$

$Q = (2 \pi) (2) \int ^R_0 \sigma * \delta (r-R) r^2 \ dr$

$Q = 4 \pi \sigma \int ^R_0 * \delta (r-R) r^2 \ dr$

$Q = 4 \pi \sigma *R^2$ since $( \int ^{xo}_{0} (x -x_o) f(x) \ dx = f(x_o) )$

$\mathbf{Q = 4 \pi R^2 \sigma }$

6 0

3 years ago

A rock is dropped from the top of a tall tower. Half a second later another rock, twice as massive as the first, is dropped. Ign

Gemiola [76]

B- the acceleration is greater for the more massive rock

5 0

2 years ago

Read 2 more answers

I need help doing this i don’t understand what to do

Hatshy [7]

Answer:

You need to write an essay with 800 to 1,200 words. That talks about the significance of one of the seminal works (Definition- a work that strongly influenced people. Example: Martin Luther King Jr's speech "I Have A Dream") in the unit and how it connects to current issues (Example- Politics). It should be clearly stated and should be well supported by research (Example- a trustworthy article talking about its influence). You should properly cite at least 3 good sources from different perspectives. (Example- a republicans view for one source, a democratic for another, and a neutral for the third) You should also use direct quotes (Example: "Let them eat cake." - Marie Antoinette) and paraphrase- put it in your own words. (Example: Marie Antoinette said that they should eat cake.) I hope this helps, good luck! :)

Explanation:

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3 years ago

Before the experiment, the total momentum of the system is 2.5 kg m/s to the right and the kinetic energy is 5J. After the exper

finlep [7]

Answer:

Option (b) is correct.

Explanation:

Elastic collision is defined as a collision where the kinetic energy of the system remains same. Both linear momentum and kinetic energy are conserved in case of an elastic collision.

Inelastic collision is defined as a collision where kinetic energy of the system is not conserved whereas the linear momentum is conserved. This loss of kinetic energy may due to the conversion to thermal energy or sound energy or may be due to the deformation of the materials colliding with each other.

As given in the problem, before the collision, total momentum of the system is $2.5~Kg~m~s^{-1}$ and the kinetic energy is $5~J$ . After the collision, the total momentum of the system is $2.5~Kg~m~s^{-1}$ , but the kinetic energy is reduced to $4~J$ . So some amount of kinetic energy is lost during the collision.

Therefor the situation describes an inelastic collision (and it could NOT be elastic).

5 0

3 years ago