To solve this problem it is necessary to apply the concept related to wavelength, specifically when the wavelength is observed from a source that is in motion to the observer.
By definition the wavelength is given defined by,

Where
= Observed wavelength
= Wavelength of the source
c = Speed of light in vacuum
u = Relative velocity of the source to the observer
According to our data we have that the wavelength emitted from the galaxy is 1875nm which is equal to the wavelength from the source, while the wavelength from the observer is 
Therefore replacing in the previous equation we have,




Solving for u,







Therefore the speed of the gas relative to earth is 0.02635 times the speed of light.
The ball's horizontal component of velocity (ie it's horizontal speed) is 20 cos 40degrees. Without knowing the distance of the ball to the wall it's difficult to go further ...
Answer:
3m
Explanation:
If a girl is 5m away from a mirror, she needs to walk a further 3m to be 2m away from her image.
5m-3m = 2m
Horizontal component of force = 100cos(36)= 80.9 N
The question is incomplete. The mass of the object is 10 gram and travelling at a speed of 2 m/s.
Solution:
It is given that mass of object before explosion is,m = 10 g
Speed of object before explosion, v = 2 m/s
Let
be the masses of the three fragments.
Let
be the velocities of the three fragments.
Therefore, according to the law of conservation of momentum,


So the x- component of the velocity of the m2 fragment after the explosion is,

∴ 