B. It's an example of velocity due to the fact that it has a measurement of speed, divided by time, and has a specific direction. Acceleration doesn't have any direction on it, but has speed divided by time. C and D have a different mode of measurement despite of the fact that it still needs meters/miles/km.
Answer:
The mass is 
Explanation:
From the question we are told that
The extension of the rod is 
The area is 
The density increase as follows 
The equation 
at 
So
=> 
So at 
, 
So
=> 
Now
![m = 8 [{2.5 +\frac{ 1.27x^2}{2} } ]\left | 13} \atop {0}} \right.](https://tex.z-dn.net/?f=m%20%20%3D%20%208%20%20%20%5B%7B2.5%20%2B%5Cfrac%7B%201.27x%5E2%7D%7B2%7D%20%7D%20%5D%5Cleft%20%20%7C%2013%7D%20%5Catop%20%7B0%7D%7D%20%5Cright.)
![m = 8 [{2.5 +\frac{ 1.27(13)^2}{2} } ]](https://tex.z-dn.net/?f=m%20%20%3D%20%208%20%20%20%5B%7B2.5%20%2B%5Cfrac%7B%201.27%2813%29%5E2%7D%7B2%7D%20%7D%20%5D)
<span>As the charged insulating rod approaches the sphere (not in contact), free electrons in the sphere move. If the rod is negatively charged, free electrons move to the side of the sphere opposite the side with the rod. If the rod is positively charged, the free electron moves to the side of the sphere with the rod. In either case, the region of the sphere near the rod acquires a charge with the sign opposite to that on the rod.
a. Since opposedly charged objects always attract each other, the rod and ball always experience mutual attractive forces.
b. Since
the side of the sphere near the bar always has the opposite charge to
the charge of the rod, the rod and the sphere always attract each other. <span>They do not repel each other.</span></span>
