Answer:
Correct answer letter b.
Explanation:
When the book is on the top shelf of the bookcase, it just only gravitational potential energy, due to the gravitational field and the kinetic energy at this point is zero because the book is at rest.
Now, when the book starts falling, all the potential energy will transform into the kinetic energy. It happens, thanks to the conservation of the energy,that says energy can neither be created nor destroyed, energy can only be transferred or changed from one form to another.
Let's recall that the gravitational potential energy depends on the object's position, so when the book falls, the magnitude of the position decreases and the speed of this object increases.
Therefore, the potential energy of the book decreases as kinetic energy increases.
Correct answer letter b.
I hope it helps you!
A compound is made up of two or more of atoms that are bonded together with each other via a chemical bonding. It is possible to break the compounds into separate smaller components by the process of chemical reaction. One very simple example of compound is water as it is made of two atoms of hydrogen and one atom of oxygen. Whenever atoms are joined together to create a compound, the atoms definitely loose their individual atomic properties. Other very commonly found compound is carbon dioxide. It is made up of one atom of carbon and two atoms of oxygen.
Answer: Gradient Wind
Explanation:
Gradient wind, is the wind that accounts for air flow along a curved trajectory. It is an extension of the concept of geostrophic wind; for example the wind assumed to move along straight and parallel isobars (lines of equal pressure). The gradient wind represents the actual wind better than the geostrophic wind, especially when both wind speed and trajectory curvature are large, because they are in hurricanes and jet streams.
Answer:
The distance from the radio station is 0.28 light years away.
Solution:
As per the question:
Distance, d = 4 ly
Frequency of the radio station, f = 854 kHz = 
Power, P = 50 kW = 

Now,
From the relation:
P = nhf
where
n = no. of photons/second
h = Planck's constant
f = frequency
Now,

Area of the sphere, A = 
Now,
Suppose the distance from the radio station be 'r' from where the intensity of the photon is 



Now,
We know that:
1 ly = 
Thus

It is round or say spherical to widen the range of photography and it is designed to focus the image as the ray are coming from infinity so !!
I am not an expert of camera but ya it is the main theme !!