Two water balloons of mass 0.35 kg collide and bounce off of each other
without breaking. before the collision, one water balloon moved at a velocity
of 2.5 m/s east, while the other moved at a velocity of 2.25 m/s west. after
the collision, one balloon moves at a velocity of 1.75 m/s west. what is the
velocity of the other water balloon?
o
a. 2 m/s west
o
b. 0.25 m/s east
o
c. 0.25 m/s west
o
d. 2 m/s east

Option D

2 m/s East

Explanation:

From the law of conservation of momentum, the sum of initial momentum equals the sum of final momentum

Momentum, p=mv where m is the mass and v is the velocity

Since the masses are the same then

Therefore

where and are final velocities of objects while and are the initial velocities respectively

Taking East direction as positive then West as negative and by substitution

Therefore

hence East since it's positive

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.