Answer:
0.0078 N
Explanation:
The electrostatic force between two charges is given by Coulomb's law:
where:
is the Coulomb's constant
are the two charges
r is the separation between the two charges
The force is attractive if the two charges have opposite sign, and repulsive if the two charges have same sign.
In this problem, we have:
located at 
located at 
located at 
The force between charge 1 and charge 2 is:

And since the two charges have opposite sign, the force is attractive, so the force on charge 1 is towards the right.
The force between charge 1 and charge 3 is:

And since the two charges have same sign, the force is repulsive, so the force on charge 1 is towards the left.
Therefore, the net force on charge 1 is:

towards the right.
Explanation:
Given
initial speed(u)=3 m/s
mass of each ball is m
Let the cue ball is moving in x direction initially
In elastic collision Energy and momentum is conserved
Let u be the initial velocity and
be the final velocity of 8 ball and cue ball respectively

The angle after which cue ball is deflected is given by

Conserving momentum in x direction


Along Y axis


substitute the value of 
we get 

Newton's first law is called inertia, or the force an object has to resist unbalanced forces that are placed upon it. The more mass an object has, the more inertia an object has. The less mass an object has, the less inertia an object has.