Forces in the universe that act over long distance, meaning the distance is greater than the diameter of the nucleus of the atom are:
1. Electrostatic force or Coulomb force: Fc=(k*Q₁*Q₂)/r²,
2. Gravitational force: Fg=(G*m₁*m₂)/r²,
3. Magnetic force: Fm=qvB,
4. London dispersion force, also known as one of the van der Waals forces.
The value of the underlined 8 is, hundred billion's. Hope this helped!
The distance covered by the acorn is 3.136 m.
<u>Explanation:</u>
The time taken for the acorn to hit the ground is 0.8 s. As it is a free fall, the acorn will be completely under the influence of gravity. So the acceleration will be acceleration due to gravity.
Then using the second law of equation,

Since the initial velocity and time is zero, then the time taken to reach the ground is stated as 0.8 s, so

So the distance covered by the acorn is 3.136 m.