The correct answer is
<span>c. one person exerts more force than the other so that the forces are unbalanced.
In fact, the door is initially at rest. In order to move the door, a net force different from zero should be applied, according to Newton's second law:
</span>

<span>where the term on the left is the resultant of the forces acting on the door, m is the door mass and a its acceleration.
In order to move the door, the acceleration must be different from zero. But this means that the resultant of the forces acting on it must be different from zero: this is possible only if the forces applied by the two persons are unbalanced, i.e. one person exerts more force than the other.</span>
1. The property of a conductor by virtue of which it posses the flow of electric current through it is called resistance.
2. The resistance of a conductor depends on the cross sectional area of the conductor and it's resistivity.
3.This id due to the fact that the resistance of a wire is inversely proportional to the square of its diameter.
4.Due to at high temperatures , the alloy donot oxidize. Alloy doesn't melt readily and get deformed.
Answer:

Explanation:
We must use conservation of linear momentum before and after the collision, 
Before the collision we have:

where these are the masses are initial velocities of both players.
After the collision we have:

since they clong together, acting as one body.
This means we have:

Or:

Which for our values is:
