Answer:

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Explanation:
Given


Required
Determine the vertical and horizontal components
The vertical (Vy) and horizontal (Vx) components is calculated as thus:


Calculating Vertical Components:




<em> --- Approximated</em>
Calculating Horizontal Components:




<em>--- Approximated</em>
Answer:
The velocity of the police car is, v = 17.798 m/s
Explanation:
Given data,
The actual frequency of the siren, f = 2010 Hz
The observed frequency of siren is, f' = 2120 Hz
The velocity of the observer, v' = 0 m/s
The velocity of the source, v = ?
The formula for Doppler effect,

Where,
V - velocity of sound waves in air.

Substituting the given values,

v = 17.798 m/s
Hence, the velocity of the police car is, v = 17.798 m/s
While self-gravity pulls the star inward and tries to make it collapse, thermal pressure (heat created by fusion) pushes outward. These two forces cancel each other out in a main sequence star, thus making it stable.
Answer:
Transfer of molecules due to density-difference resulting from increased temperature of the layers of fluid bulk leads to convection.
Explanation:
When a mass of fluid is heated form the lower layers then due to the variation of the density of the fluid at different temperature we observe the movement of molecules leading to convection.
- When the lowest level of the fluid is heated it gains temperature and the molecular bulk expands on heating and its density becomes low with respect to the bulk fluid around it and hence it flows upwards to the top most layer being lighter in weight and the lowest layer is occupied by the subsequent colder and denser layer.
- Then again the lowest layer is heated and the process continues forming a cycle heating through the bulk transfer of fluid layers called convention.