a closed system does not allow matter or energy to pass through
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Answer:
v = 0.99 c = 2.99 x 10⁸ m/s
Explanation:
From the special theory of relativity:

where,
v = speed of travel = ?
c = speed of light = 3 x 10⁸ m/s
t = time measured on earth = 90 years
t₀ = time measured in moving frame = 6 months = 0.5 year
Therefore,

<u>v = 0.99 c = 2.99 x 10⁸ m/s</u>
Answer:
Explanation:
The momentum of the first piece = m v =- m x 31 i kg m/s in - x direction direction
The momentum of the second piece = -m x 31 j kg m /s in Y - direction
Total momentum = - 31 m( i + j )
To conserve momentum , the third piece must have momentum equal to this
and opposite to it
So momentum of the third piece = 3m x V = 31 m ( i +j )
V = 31/3 ( i + j ) =
Magnitude of velocity V = √2 x 31/ 3 = 14.6 m / s
Its direction will be towards the vector i + j ie 45° from x - axis in positive direction
Answer:
The degree of reflection whether faint or bright you see on the surface of an object is an indication that light particles had hit the surface. Since light is a wave and as part of its characteristics can get reflected. However, the amount of light reflected by a surface is dependent on the smoothness of the surface which can be shiny or dull, it can also be dependent on the nature of the surface which can be glass, water, and so on. So, from the question, you can see a faint reflection on the surface of a shiny plate or cup because of the smoothness of the surface which reflects the lights that hit it from a particular direction at the same angle.