Answer:
Explanation:
The explanation is given in the attached document.
Answer:

Explanation:
The water droplet is initially neutral, it will obtain a 40 nC of charge when a charge of -40 nC is removed from the water droplet.
The charge on one electron, 
Let the N number of electrons have charge -40 nC, such that,
Now, mass of one electron = 
Therefore, mass of N electrons = 
It is the mass of the of the water droplet that must be removed in order to obtain a charge of 40 nC.
Let it is m times the total mass of the droplet which is 
Then,

It is the required fraction of mass of the droplet.
Answer:
I only know how to answer 22
which is 250 J
Explanation:
KE: 1/2 mv^2
m- 5kg
v- 10 m/s
KE: 1/2 × 5 × 10^2
= 250 J