Calcular la aceleración (en m/s2) que se aplica para que un móvil que se desplaza en línea recta a 90 km/h reduzca su velocidad a 50.0 km/h en 25 segundos.

a = 0.44[m/s²]

Explanation:

Para solucionar este problema debemos de utilizar la siguiente ecuacion de la cinematica.

donde:

Vf = velocidad final = 50 [km/h]

Vo =  velocidad inicial = 90 [km/h]

a = desaceleracion [m/s²]

t = tiempo = 25 [s]

Pero primero debemos convertir la velocidad de kilometros por hora a metros por segundo.

Ahora podemos reemplazar en la ecuacion:

Nota: El signo de la aceleracion se cambia a negativo, ya que el vehiculo disminuye la velocidad.

answer: the rock sample is a sedimentary rock.

explanation:

it is given that:

mass of rock sample, m = 2.7 g

volume of rock sample,

so, density of rock sample will be

since, the density of rock sample is . hence, the rock sample is a sedimentary rock, whose densities varies between .

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.