PLEASE HELP I HAVE BEEN STUCK ON THIS FOR A WHILE. A long platform is holding your physics teacher in the air above some hungry alligators. Your physics teacher has a mass of 75 kg and is located 2 m from one end. The 10.0 m platform has a mass of 10.0 kg, and its center of gravity is located 4.0 m from the same end. The platform is being held up by two students, one at either end.

a. What force is required by each student to hold the platform up?

See Below.

Explanation:

I can't transpose the diagram onto I'll do my best to describe what is going on.

Now you are ready to develop the equation

Clockwise

There is only 1 force where B is the Balance point that is going clockwise

10 * Force A

The AntiClockwise Moments

Platform: 4*10kg * 9.8 = 392 N m

Physics T: 2 * 75 * 9.8 = 1470 N m

So the Anti Clockwise moments = the clockwise moments.

10 * Force A = 392 NM  + 1470NM   Divide by 10. Remember that is in meters

Force A = 1862 N M / 10 10 M = 186 N

Does that make some sort of sense? It should Student A is the furthest distance from where all the action is at B. Therefore he is carrying the lightest weight.

Now what is the total force?

(75 + 10 ) * 9.8 = 85 * 9.8 = 833

This is one of those strange things that won't make sense until it does. Read the next sentence carefully. B is carrying most of the weight. Remember Newtons measure weight.

Support of A = 186 N

Support of B = x

Total of A+B = 933

186 + x = 833

x = 933 - 186

x = 647

So the forces are

A supports    186

B supports    647

he made 11 calls in one day

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.