Answer:

Explanation:
= Avogadro's number = 
e = Charge of electron = 
k = Coulomb constant = 
Z = Atomic number of water = 18
M = Molar mass of water = 0.018 kg/mol
m = Mass of person
The charge is given by

Total number of protons and electrons in each sphere




Electrical force is given by

The electrostatic force of attraction between them is 
Answer:
A type of telescope that does not require darkness in order to be able to use it is the refracting telescope
Explanation:
A refracting telescope consists of a lens and an eyepiece collects light which is then focused to present a magnified, bright and clear image.
The incident light on a refracting telescope is bent by refraction such that the light is focused to the focal point.
In refracting telescopes, the image is formed by bending light, that is by refraction.
The refracting telescope technology has been applied to binoculars and camera zoom lenses.
I think your answer would be DDT, but don't hold me to it
Answer:
Electric field, 
Explanation:
It is given that,
Mass of sphere, m = 2.1 g = 0.0021 kg
Charge, 
We need to find the magnitude of electric field that balances the weight of a plastic spheres. So,

a = g



or

Hence, the magnitude of electric field that balances its weight is
. Hence, this is the required solution.
Answer:
Final speed of boat + man is 1.66 m/s
Explanation:
As we know that there is no friction on the system or there is no external force on this system
So here we can use momentum conservation here

so we have
m = 85 kg
M = 135 kg
v = 4.30 m/s
now we have

