Answer:
the source of sound moves towards an observe
Explanation:
The Doppler effect is related to waves such as sound or light. the effect causes an increase or decrease in the frequency of sound light or other waves when the souces either move towards or away from the observer. For example the siren of the train to a person on the platform, the redshift seen by astronomers.
Therefore, The Doppler shift can be observed when the source of sound moves towards an observer From a place closer to the observer than the last wave's crest, each consecutive wave crest is sent. Each wave therefore, takes a little less time than the preceding wave to reach the observer.
To solve this problem it is necessary to apply the concepts related to the Centrifugal Force and the Gravitational Force. Since there is balance on the body these two Forces will be equal, mathematically they can be expressed as


Where,
m = Mass
G =Gravitational Universal Constant
M = Mass of the Planet
r = Distance/Radius
Re-arrange to find the velocity we have,

At the same time we know that the period is equivalent in terms of the linear velocity to,


If our values are that the radius of mars is 3400 km and the distance above the planet is 100km more, i.e, 3500km we have,



Replacing we have,



Therefore the correct answer is C.
So the best conductor for electricity is silver.
However because silver is so expensive we use copper which is the next best conductor
Answer: Mechanical waves
Explanation:
Mechanical waves require a medium in order to transport their energy from one location to another. A sound wave is an example of a mechanical wave. Sound waves are incapable of traveling through a vacuum.
Answer:
v = 1.15*10^{7} m/s
Explanation:
given data:
charge/ unit area
plate seperation = 1.69*10^{-2} m
we know that
electric field btwn the plates is
force acting on charge is F = q E
Work done by charge q id
this work done is converted into kinectic enerrgy

solving for v



v = 1.15*10^{7} m/s