A 1600 kg car is moving north with a speed of 25 m/s. An impulse of 10,000 N-s south is applied to the car. After the impulse is applied, the speed of the car is:

The speed of the car is 18.75 m/s

Explanation:

Impulse-Momentum Change Equation

The impulse received by an object is equal to the change in momentum:

Impulse = Change in momentum

The change in momentum is:

Where m is the mass of the object, v2 is the final speed, and v1 is the initial speed. This means the impulse J is:

It's given an m=1,600 kg car is moving at v1=25 m/s North and then an impulse of J=-10,000 N.s is applied South. The minus sign indicates the impulse is opposite to the original direction of the velocity.

Solving for v2:

Substituting:

The speed of the car is 18.75 m/s

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.