The center of mass is given with this formula:

Velocity is:

So, for the velocity of the center of mass we have:

In our case it is:
Answer:
A: In all cases, the acceleration was the same.
Explanation:
I know this because its a clear obvious answer not only that it was one of my USA TESTPREP questions and it was right.
All you mainly have to do is the math - F=ma , In each case , the acceleration is 5 m/s squared
Answer: 
Explanation:
A direct proportionality means a linear relationship between two variables and rate of change means an application of derivatives. Hence, the mathematical model is:
