Because the weight of one ball is mg = 147 N, the gravitational force between the two balls is 
or 
parts per billion of the weight.
Answer:
A- The ball has both kinetic and potential energy,
Explanation:
kinetic energy by virtue of its motion.
potential energy by virtue of its position. (It could roll off the edge of the tabel and convert gravity potential energy to kinetic energy)
Answer:
The acceleration of the ball as it rises to the top of its arc equals 9.807 meters per square second.
Explanation:
Let suppose that maximum height of the arc is so small in comparison with the radius of the Earth.
Since the ball is launched upwards, then the ball experiments a free-fall motion, that is, an uniform accelerated motion in which the element is accelerated by gravity. Then, the acceleration experimented by the motion remains constant at every instant and position.
Besides, the gravitational acceleration in the Earth and, in consequence, the acceleration of the ball as it rises to the top of its arc equals 9.807 meters per square second.
In atoms, electrons surround the nucleus in specific energy levels.
Answer: Option B
<u>Explanation:
</u>
Atom, actually considered as the tiny part that is ever present in this universe. Many theories and experiments were conducted, for studying what was present inside of an atom, and many theories came into light.
And finally, Bohr-Sommerfeld Theory stated the final conclusion, that the positive charge is at the centre of the nucleus, and all the electrons revolve in their specific energy levels. If an atom wants to move to lower energy state, it should emit energy, whereas for going to higher state, it should gain energy.
