In an open system such as a campfire, matter can lose particles, gain particles or exchange particles.
Answer:
As of right now the techology has not been invented to time travel
if we were to time travel to the future from where that person travled from would be the past and to them the people from where they came from are living in the past
Explanation:
The emerging velocity of the bullet is <u>71 m/s.</u>
The bullet of mass <em>m</em> moving with a velocity <em>u</em> has kinetic energy. When it pierces the block of wood, the block exerts a force of friction on the bullet. As the bullet passes through the block, work is done against the resistive forces exerted on the bullet by the block. This results in the reduction of the bullet's kinetic energy. The bullet has a speed <em>v</em> when it emerges from the block.
If the block exerts a resistive force <em>F</em> on the bullet and the thickness of the block is <em>x</em> then, the work done by the resistive force is given by,

This is equal to the change in the bullet's kinetic energy.

If the thickness of the block is reduced by one-half, the bullet emerges out with a velocity v<em>₁.</em>
Assuming the same resistive forces to act on the bullet,

Divide equation (2) by equation (1) and simplify for v<em>₁.</em>

Thus the speed of the bullet is 71 m/s
Answer:
No, The Moon, on the other hand, rotates once around its every 28 days, and once around the Earth in that same 28 days. The result of this combination is that the same side of the Moon is always facing the Earth.