Answer:
Rest and motion are the relative terms because they depend on the observer's frame of reference. So if two different observers are not at rest with respect to each other, then they too get different results when they observe the motion or rest of a body.
Explanation With Example:
Imagine you are sitting inside a moving bus. When you look outside you will observe that you are moving. ... With respect to the roof of bus, you are at rest. Hence it is concluded that rest and motion are relative terms.
Explanation:
Given that,
Object distance u= -110 cm
Image distance v= 55 cm
We need to calculate the focal length for diverging lens
Using formula of lens
Put the value into the formula
The focal length of the diverging lens is 36.6 cm.
Now given a thin lens with same magnitude of focal length 36.6 cm is replaced.
Here, The object distance is again the same.
We need to calculate the image distance for converging lens
Using formula of lens
Here, focal length is positive for converging lens
The distance of the image is 54.85 cm from converging lens.
Hence, This is the required solution.
Answer:
The era of planet formation ended when the remaining hydrogen and helium gas of the solar nebula was swept into interstellar space by the solar winds.
Explanation:
The Solar System is formed from a molecular cloud (compound by gas and dust). If there is a near perturbation to the cloud, maybe due to a supernova explosion, the molecular cloud will collapse under its own gravity. Then, in some point it starts to rotate and will accrete all the material in a disk around the protostar¹.
Inside the disk, dust particles start to collide and accrete until they form planetesimals². As a consequence of the gravitational force of the star, rocky and metallic particles will be more attracted to the inner part of the Solar System (close to the Sun) since they have more mass than gas.
Then, when the star has the necessary pressure and temperature to initiate nuclear reactions in its core, it will be able to emit huge amounts of energy, better known as solar winds. These winds will expel gas (hydrogen and helium) from the Solar System more easily than the rocky and metallic particles.
Notice that when such event occurs, rocky and gaseous planets were already formed.
Key terms:
¹Protostar: A young star.
²Planetesimals: Object formed by many fragments due to the gravitational attraction between them.
Answer:
At the high temperatures of the inner solar nebula, the small proto-planets were too hot to hold the volatile gases that dominated the solar nebula. These proto-planets were Earth, Mars, Venus, and Mercury.
Explanation:
The materials that accreted into the early Earth were probably added piecemeal, without and particular order. The early earth was very hot from gravitational compression, impacts and radioactive decay; the earth was partially molted. The denser metallic liquids sank to the center of the Earth and less denser silicate liquids rose to the top. In this way the Earth differentiated very quickly into a metallic, mostly iron core and a rocky silicate mantle.
