You and a friend are playing tug-of-war with a massless rope. You are pulling with 50 Newtons of force while your friend is pulling with 40 Newtons of force.
What is the tension in the rope?
What is your net force?
What is your friend’s net force?

Explanation:

A tug of war is game where two teams will be pulling a rope horizontally,

So,

Given that,

You applied a force of F1 = 50N

You friend you are pulling against applied a force of F2 = 40N

A. Tension on the rope.

Let the tension on the rope be T

The tension cause by you on the rope is the force you applied

T = 50N.

The tension cause by your friend is also

T = 40N

Adding the two tension together

T+T = 50+40

2T = 90

T = 45

OR you will see the rope as a pulley system, i.e. we will assume that the two friend force cause a tension on the rope, their are two tension on the rope, and two forces are applied

Then, tension is equal to force applied

T+T = 40+50

2T = 90

T = 45N

b. Net force by you

In this case we will take your position as the positive direction, I.e. the net force cause by you

Using newton second law

Fnet. = ΣFx

Fnet = F1—F2

Fnet = 50—40

Fnet = 10 N

c. Fnet by your friend

In this case we will take your friends position as the positive direction, I.e. the net force cause by your friend.

Fnet. = ΣFx

Fnet = F2—F1

Fnet = 40—50

Fnet = —10 N

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.