3. Pete needs to be at work for 10.00am. He leaves his house at 7.00am and drives to the gym which is 12.5 miles away. Pete spends 1 hour in the gym then drives 30minutes the remaining

9 miles to work.

a. What average speed in, miles per hour, must Pete drive at to ensure he is not late for

work?(3 marks)

I

grav potential energy

false br

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.

causes

fossil fuels burn

cities become more industrialized

human population grows worldwide