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3 years ago

An unmanned spacecraft leaves for Venus. Which statements about the spacecrafts journey are true?

2 answers:

4 0

<span>The weight of the spacecraft keeps changing.
</span>
<span>The mass of the spacecraft remains the same.

These are the correct answers</span>

san4es73 [151]3 years ago

3 0

Answer:

A)The weight of the spacecraft keeps changing.

D) The mass of the spacecraft remains the same

Explanation:

As we know that the acceleration due to gravity depends on the height from the surface

As we know that the force due to gravity on objects near the surface is given as

$F = \frac{Gm_1m_2}{(R+h)^2}$

here we know that

R = radius of planet

h = height from the surface of planet

So as we move away at more height the gravitational attraction force will keep on decreasing.

This gravitational attraction force of planet is also known as weight so we can say that the weight of the object will keep on changing while object move away.

Also we know that mass of object is quantity of the matter which always remains constant.

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When atoms of an element are excited, they emit specific wavelengths of light. How is this similar to a fingerprint when Fraunho

Anika [276]

Answer:

As you may know, each element has a "fixed" number of protons and electrons.

These electrons live in elliptical orbits around the nucleus, called valence levels or energy levels.

We know that as further away are the orbits from the nucleus, the more energy has the electrons in it. (And those energies are fixed)

Now, when an electron jumps from a level to another, there is also a jump in energy, and that jump depends only on the levels, then the jump in energy is fixed.

Particularly, when an electron jumps from a more energetic level to a less energetic one, that change in energy must be compensated in some way, and that way is by radiating a photon whose energy is exactly the same as the energy of the jump.

And the energy of a photon is related to the wavelength of the photon, then we can conclude that for a given element, the possible jumps of energy levels are known, meaning that the possible "jumps in energy" are known, which means that the wavelengths of the radiated photons also are known. Then by looking at the colors of the bands (whose depend on the wavelength of the radiated photons) we can know almost exactly what elements are radiating them.

7 0

3 years ago

Picture showing four cards in a row with labels 'First animal appears on land', 'First life form appears in the sea', 'First roc

sasho [114]

The answer would be 'First rocks formed on Earth'.

3 0

3 years ago

A parcel has a mass of 500 g .calculate its weight (assume the gravitational field strength is 10 N/Kg

Effectus [21]

Answer:

Explanation

convert grams to kg and multipy with 10 (.5 *10)=5N

5 0

3 years ago

Calculate the average drift speed of electrons traveling through a copper wire with a crosssectional area of 80 mm2 when carryin

Vedmedyk [2.9K]

Answer:

The correct answer is $2.8*10^{-5}ms^{-1}$

Explanation:

The formula for the electron drift speed is given as follows,

$u=I/nAq$

where n is the number of of electrons per unit m³, q is the charge on an electron and A is the cross-sectional area of the copper wire and I is the current. We see that we already have A , q and I. The only thing left to calculate is the electron density n that is the number of electrons per unit volume.

Using the information provided in the question we can see that the number of moles of copper atoms in a cm³ of volume of the conductor is $8.93/63.5 molcm^{-3}$ . Converting this number to m³ using very elementary unit conversion we get $140384molm^{-3}$ . If we multiply this number by the Avagardo number which is the number of atoms per mol of any gas , we get the number of atoms per m³ which in this case is equal to the number of electron per m³ because one electron per atom of copper contribute to the current. So we get,

$n=140384*6.02*10^{23} = 8.45*10^{28}electrons.m^{-3}$

if we convert the area from mm³ to m³ we get $A=80*10^{-6}m^{2}$ .So now that we have n, we plug in all the values of A ,I ,q and n into the main equation to obtain,

$u=30/(8.45*10^{28}*80*10^{-6}*1.602*10^{-19})\\u=2.8*10^{-5}m.s^{-1}$

which is our final answer.

6 0

3 years ago

Two objects separated by a distance r are each carrying a charge q The magnitude of the force exerted on the second object by th

Sindrei [870]

Answer:F=4F

Explanation: Columbs law states that The force between the two point charges is directly proportional to the product of charges and inversely proportional to the square of distance between them

Force between the two charges is given by

F=K*q1*q2/r^2

if one charge become 4 times, new force is,

F=4(K*q1*q2)/r^2

F=4F

Where q1 and q2 are the point charges

r is the distance between the two charges

K is a constant of proportion called electrostatic force

4 0

3 years ago