I assume that the ball is stationary (v=0) at point B, so its total energy is just potential energy, and it is equal to 7.35 J.
At point A, all this energy has converted into kinetic energy, which is:

And since K=7.35 J, we can find the velocity, v:
The answer is D) neutral water reacts with carbon dioxide to form an acid solution
<span>3.2x10^-2 seconds (0.032 seconds)
This is a simple matter of division. I also suspect it's an exercise in scientific notation, so here is how you divide in scientific notation:
9.6 x 10^6 m / 3x10^8 m/s
First, divide the significands like you would normally.
9.6 / 3 = 3.2
And subtract the exponent. So
6 - 8 = -2
So the answer is 3.2 x 10^-2
And since the significand is less than 10 and at least 1, we don't need to normalize it.
So it takes 3.2x10^-2 seconds for the radio signal to reach the satellite.</span>
<span>Electric field repulsive for objects of like charge and attractive for opposite type of charges and for a magnet you can say that like poles repel and unlike attracts so D makes sense</span>
Hope this helps, if you need clarification i got you