In empty space probably means, there is no force on the ball.
(This assumption is not quite correct since there is still the force of gravity between the ball and the astronaut, but this force is very very small and can be neglected.)
Assuming there is no force on the ball, Newtown's 1st law says: When viewed in an internal frame of reference, an object either remains at rest or continues to move at a constant velocity, unless acted upon by a force.
This means:
If there is no force on the ball, there will be no acceleration on the ball either.
If the acceleration is zero, the velocity of the ball never changes.
1) The correct answer is
<span>C) The particles are not able to move out of their positions relative to one another, but do have small vibrational movements.
In solids, in fact, particles are bound together so they cannot move freely. However, they can move around their fixed position with small vibrational movements, whose intensity depends on the temperature of the substance (the higher the temperature, the more intense the vibrations). For this reason, we say that matter moves also in solid state.
2) The correct answer is
</span><span>A) increase the concentration of both solutions
In fact, when we increase the concentration of both solutions, we increase the number of particles that react in both solutions; as a result, the speed of the reaction will increase.
3) The correct answer is
</span><span>C) gas → liquid → solid
In gases, in fact, particles are basically free to move, so the intermolecular forces of attraction are almost negligible. In liquids, particles are still able to move, however the intermolecular forces of attraction are stronger than in gases. Finally, in solids, particles are bound together, so they are not free to move and the intermolecular forces of attraction are very strong. </span>
If the car's motion appears as a horizontal line on a <u><em>position-time </em></u>graph, it shows that as time changes, the car's position doesn't change.
This is just a complicated way to say that the car is <em>not moving</em>.<em> (A)</em>
By the rate of the hemisphere