A ping pong ball of mass 0.0027 kg and radius 0.020 m is completely submerged 0.3 m in water. How fast is it moving when it emerges from the water?

The value speed  is  

Explanation:

From the question we are told that

   The mass of the ping pong ball is

    The  radius is  

     The depth of the ping pong inside the water is  

Gnerally the force with which the ball will emerge will from the water is mathematically represented as

Here B  is the Buoyant force on the ball which is mathematically represented as

Here   is the volume of the ball which is mathematically represented as

=>    

=>    

         is the density of water with value  

So  

=>    

So

=>  

=>  

Generally force is mathematically represented as

So

=>  

Generally  from kinematic equation

Here u  is the velocity of the ping pong at depth of  0.3 m and the value is zero given that at that point there was no motion

So

=>    

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.