D. The answer is D because any other scenario is possible. For example, in A, John could very easily put the planets in order. In problem B, he could draw some planets bigger than others. On C, he could color the planets on a different color. He can not hovever, move the planets
Covalent bond occurs due to chemical reaction
I would say NASA because she wants to her hands on + there is a NASA research center in Hampton, Virginia!
The universal law of gravitation says that the gravitational force between the two masses is
<em>F</em>₁ = <em>G</em> <em>m</em>₁ <em>m</em>₂ / <em>r</em> ² = 6.0 × 10⁻⁶ N
where <em>r</em> = 12 m. When the distance between the two masses is reduced to <em>R</em> = 4 m, i.e. 1/3 of the original distance <em>r</em>, we have
<em>F</em>₂ = <em>G</em> <em>m</em>₁ <em>m</em>₂ / <em>R </em>² = <em>G</em> <em>m</em>₁ <em>m</em>₂ / (<em>r</em>/3)² = 1/9 <em>G</em> <em>m</em>₁ <em>m</em>₂ / <em>r </em>² = 1/9 <em>F</em>₁
so that the resulting gravitational force has 1/9 the first magnitude, or
<em>F</em>₂ = 1/9 (6.0 × 10⁻⁶ N) ≈ 6.7 × 10⁻⁷ N
