Protons and neutrons are packed together in a very small region called nucleus. Protons are positively charged and we know that like charges repel. Then how is it that protons are not repelling each other and flying away from nucleus?
You may think that gravitational force is holding all the protons together but it is not so. Gravitational force is many times weaker than repulsive force.
It is actually strong force which holds proton together. At this short distance, strong force comes into play and is several times stronger than the repulsive force.
Answer:
B
Explanation:
Newton's first law of motion states that a body will remain in its state of rest or if its in motion will continue to move in a straight line, unless its acted upon by an external force.The ability of an object to stay at rest or in motion if its in motion is known as inertia.
Hence the correct option is B.
Answer:

Explanation:
Let the charge on the ball bearing is q.
charge on glass bead, Q = 20 nC = 20 x 10^-9 C
Force between them, F = 0.018 N
Distance between them, d = 1 cm = 0.01 m
By use of Coulomb's law in electrostatics

By substituting the values


Thus, the charge on the ball bearing is 
Answer:
the force exerted by the seat on the pilot is 10766.7 N
Explanation:
The computation of the force exerted by the seat on the pilot is as follows:

Hence, the force exerted by the seat on the pilot is 10766.7 N