Una empresa reparte paquetes a sus clientes con un pequeño dron. Las aspas horizontales giratorias ejercen una fuerza sobre el aire circundante. El aire por encima de la aeronave está inicialmente inmóvil. El aire es impulsado verticalmente hacia abajo con rapidez v. La aeronave se mantiene inmóvil sobre el suelo. Un paquete está suspendido de la aeronave con una cuerda. La masa de la aeronave es 0.95 kg y la masa combinada del paquete y la cuerda es de 0.45 kg. La masa de aire empujada hacia abajo por las palas en un segundo es 1.7kg . Escriba el valor de la fuerza resultante sobre la aeronave cuando ésta se encuentra suspendida.

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.

a. vertically

explanation:

i tried it and took the test

if im wrong then we have different tests