The electrostatic force between two charges q1 and q2 is given by

where

is the Coulomb's constant

is the distance between the two charges.
In our problem, the two charges are two electrons, so their charges are equal and equal to

By substituting these values, we find the intensity of the force between the two electrons:

This is the magnitude of the force each electron exerts to the other one. The direction is given by the sign of the charges: since the two electrons have same charge, they repel each other, so the force exerted by electron 1 is toward electron 2 and viceversa.
Answer:a) Water is relatively resistant to an increase in temperature
Explanation:
Water has relatively high heat capacity i.e. it requires high amount of heat to raise a little increase in temperature.
Heat capacity is defined as ability of molecule to absorb heat . Mathematically heat capacity is defined as

where 

Answer:
W = 0.012 J
Explanation:
For this exercise let's use Hooke's law to find the spring constant
F = K Δx
K = F / Δx
K = 3 / (0.16 - 0.11)
K = 60 N / m
Work is defined by
W = F. x = F x cos θ
in this case the force and the displacement go in the same direction therefore the angle is zero and the cosine is equal to 1
W = ∫ F dx
W = k ∫ x dx
we integrate
W = k x² / 2
W = ½ k x²
let's calculate
W = ½ 60 (0.19 -0.17)²
W = 0.012 J