Answer:
a) Yes, this is kinda the best way to split the teams.
b) Force (or acceleration, these are proportional)
Explanation:
For both questions, we should start with the second Newton's law.
This law can be written as:
F = m*a
force equals mass times acceleration.
a) For the case of the rope, the ideal situation is having almost the same mass in both ends of the rope, in this way, the relation between force and acceleration in each end will be equivalent. (while one could argue that 3 smaller people will actually have a larger mass than the two bigger ones) but yes, this way is a good way to split the teams, so the mass is as even as possible.
b) Acceleration is defined as the rate of change of the velocity.
Again, by the above equation:
F = m*a
We need to have a force if we want to have acceleration.
Then, if an object has constant velocity (if the object is at a full stop, then it has a constant velocity of 0 m/s) we need to apply a force to this object if we want to change its motion.
Similarly, if an object is accelerating, we can apply a force to the object in order to cancel that acceleration (if the net force applied in the object is zero, then the acceleration is zero)
So here we can conclude that a force is what causes an object to change its motion.
