Answer:
The box will move towards me by the additional force of 60N.
Explanation:
I am pulling the box with a force of 30N and my friend is pushing the box in the same direction with a force of 30N.
Here two forces are exhibited in the same direction that is towards myself as a result the box will move towards me by an additional force of 30N+30N=60N.
A solid with a unit cell that follows a structure to the face-centered cubic crystal would look like that shown in the attached picture. Thus, the model should consist of 8 balls, one for each corner of the cube. Also, It would need 6 balls, one at each center of the cube's faces. So, the answer is A.
That friend is not correct. Physical change is characterized by a change in appearance without any change in composition. So, if the appearance did not change in the situation, then there is no change in the system. This type of change affects the form of a substance but not the composition or the structure of the molecules. Examples of this type of change are ice melting, cutting a paper into half, clay is molded to a new shape, butter melting, water evaporating. The change that involves a change in chemical composition is classified a chemical change. In this type of change, chemical reactions would take place.
The volume increased to 0.64 L on increasing the temperature to boiling point of water.
<u>Explanation:</u>
One of the important laws used for understanding the kinetics of gas particles is Charle's law. It states that the volume occupied by gas molecules will be directly proportional to the Kelvin temperature of the molecules at constant pressure.
Volume ∝ Kelvin Temperature at constant Pressure
So, in this case, the initial volume of the container in which Nitrogen gas is kept is given as 0.5 L and the initial temperature of the Nitrogen gas is said to be 18°C.
Now the container is heated to boiling point of water which is 100°C, then the volume occupied by the gas should increase as per Charle's law.

Since here V₁ = 0.5 L
T₁ = 18°C = 18 + 273.15 = 291.15 K
T₂ = 100°C = 100 + 273.15 = 373.15 K

Thus, the volume increased to 0.64 L on increasing the temperature to boiling point of water.