Where is most of the dark matter believed to be found in the galaxy?
2 answers:
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Answer:
Explanation:
According to the law of conservation of linear momentum, the total momentum of both pucks won't be changed regardless of their interaction if no external forces are acting on the system.
Being and
the masses of pucks a and b respectively, the initial momentum of the system is
Since b is initially at rest
After the collision and being and
the respective velocities, the total momentum is
Both momentums are equal, thus
Solving for
The initial kinetic energy can be found as (provided puck b is at rest)
The final kinetic energy is
The change of kinetic energy is
Answer: c. the molecules with the highest energy evaporate first, lowering the temperature of the sample
Explanation:
The process by which liquid starts to change into vapor phase at any temperature is known as evaporation.
During evaporation , the molecules which possess higher energies escape from the upper layer into vapor phase. the molecules which escape draw energy from surroundings and thus decrease the energy of the surroundings and hence lead to decrease in temperature.
As temperature of the system is directly proportional to the energy of the system , thus decrease in energy leads to decrease in temperature.
K.E. = Kinetic energy
T = temperature
R= gas constant