Use the law of universal gravitation, which says the force of gravitation between two bodies of mass <em>m</em>₁ and <em>m</em>₂ a distance <em>r</em> apart is
<em>F</em> = <em>G m</em>₁ <em>m</em>₂ / <em>r</em>²
where <em>G</em> = 6.67 x 10⁻¹¹ N m²/kg².
The Earth has a radius of about 6371 km = 6.371 x 10⁶ m (large enough for a pineapple on the surface of the earth to have an effective distance from the center of the Earth to be equal to this radius), and a mass of about 5.97 x 10²⁴ kg, so the force of gravitation between the pineapple and the Earth is
<em>F</em> = (6.67 x 10⁻¹¹ N m²/kg²) (1 kg) (5.97 x 10²⁴ kg) / (6.371 x 10⁶ m)²
<em>F</em> ≈ 9.81 N
Notice that this is roughly equal to the weight of the pineapple on Earth, (1 kg)<em>g</em>, where <em>g</em> = 9.80 m/s² is the magnitude of the acceleration due to gravity, so that [force of gravity] = [weight] on any given planet.
This means that on this new planet with twice the radius of Earth, the pineapple would have a weight of
<em>F</em> = <em>G m</em>₁ <em>m</em>₂ / (2<em>r</em>)² = 1/4 <em>G m</em>₁ <em>m</em>₂ / <em>r</em>²
i.e. 1/4 of the weight on Earth, which would be about 2.45 N.
Time stops everything is made out of atoms so if atoms freeze everything freezes
B is the answer, I’m really good at this subject
Answer:
<u>0.04 °C⁻¹</u>
Explanation:
First, we need to calculate linear expansivity, then after finding that value, we can move on to finding the area expansivity.
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Finding Linear Expansivity :
⇒ α = Final length - Original length / (Original length × ΔT)
⇒ α = 9 - 4 / (4 × 70 - 20)
⇒ α = 5 / 5 × 50
⇒ α = <u>0.02</u>
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Finding Area Expansivity :
⇒ Area Expansivity = 2 × Linear Expansivity
⇒ β = 2 × α
⇒ β = 2 × 0.02
⇒ β = <u>0.04 °C⁻¹</u>
