The gravitational field strength on the surface of the Earth is g. The gravitational field strength on the surface of a planet of twice the radius and the same density is:
Correct answer: B. 2g
- A. 4g
- B. 2g
- C. g
- D. g/4
Explanation
The unit "per ohm second" (Ω⁻¹s) is indeed equivalent to the unit "farad" (F), which is the SI unit of capacitance. Both units represent different aspects of electrical properties. In the context of capacitance, the farad (F) measures the ability of a capacitor to store an electric charge for a given voltage. It's defined as one coulomb of charge per volt of potential difference. On the other hand, "per ohm second" (Ω⁻¹s) represents the unit of electrical conductance multiplied by time. Conductance is the reciprocal of resistance (measured in ohms), and when multiplied by time (seconds), it becomes equivalent to capacitance (farads). In mathematical terms: 1 F = 1 Ω⁻¹s This relationship highlights the interconnectedness of various electrical properties and units. Now, the gravitational field strength (g') on the surface of the new planet will be determined by the following equation: g' = G * (M' / R'²) where: G is the gravitational constant (a universal constant, approximately 6.674 × 10⁻¹¹ N(m/kg)²), M' is the mass of the planet (which is 8 times the mass of the Earth), R' is the radius of the planet (twice the radius of the Earth). Since the mass and radius are both larger by a factor of 8 and 2, respectively, the gravitational field strength on the surface of the new planet (g') will be: g' = 8g/4 = 2g Therefore, the gravitational field strength on the surface of a planet with twice the radius and the same density as the Earth will be two times the gravitational field strength on the surface of the Earth (2g). Refer to this video for better understanding:
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Newton’s law of universal gravitation relates the force between masses to their masses and separation, while gravitational field strength explains weight and orbital motion. The topic covers satellite velocity and period, escape ideas, weightlessness in free fall, and artificial gravity, which differs from ordinary gravitational attraction.
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