Answer:
Part a)

Part b)

Explanation:
Since the ball and rod is an isolated system and there is no external force on it so by momentum conservation we will have

here we also use angular momentum conservation
so we have

also we know that the collision is elastic collision so we have

so we have

also we know

also we know

so we have


now we have


Part b)
Now we know that speed of the ball after collision is given as

so it is given as

I think number 1 is incorrect I believe that answer is D. Number 6 I believe would be B. The rest seem to be correct.
Answer:
No you can't cuz,if you put water instead of clock oil in Millikan oil drop your experiment will fail and it won't turn out the way you wanted it to be
Answer:
Between 0 and 1 seconds (B)
Explanation:
The velocity of the car over time is represented by the line graphed here
the steeper the line, the greater change in velocity that occurred in a given time frame.
The steepest portion of the line is between 0-1 seconds, which means that the greatest rate of change occurred between 0-1 seconds.
(acceleration is the rate of change)