Question

practice it!
the table contains data about the properties of inner planets.
select the correct statement(s).
the gravity on mercury and mars is the same because mercury has less mass than mars, but it is closer to the sun.
the gravity of a planet increases as its mass decreases and its distance from the sun increases.
the gravity on mercury and mars is the same because mercury has more mass than mars, but it is farther from the sun.
the gravity of a planet is not affected by its mass or its distance from the sun.
the gravity of a planet increases as its mass increases and its distance from the sun decreases.

Explanation:

• Gravity of a planet is calculated by \(g=\frac{GM}{R^{2}}\) (where \(G\) is gravitational constant, \(M\) is mass of the planet and \(R\) is the distance from the Sun).
• For the first option: Mercury has mass \(M_{M}=0.06\) (relative to Earth’s) and Mars has \(M_{Ma} = 0.11\) (relative to Earth’s). So Mercury has less mass than Mars. But gravity is not only about distance from Sun.
• For the second option: From \(g=\frac{GM}{R^{2}}\), as \(M\) (mass) decreases and \(R\) (distance from Sun) increases, \(g\) (gravity) decreases.
• For the third option: Mercury has less mass than Mars.
• For the fourth option: Gravity of a planet is affected by its mass (\(M\)) and its distance from the Sun (\(R\)) as \(g=\frac{GM}{R^{2}}\).
• For the fifth option: As \(M\) (mass) increases and \(R\) (distance from Sun) decreases, from \(g = \frac{GM}{R^{2}}\), \(g\) (gravity) increases.

Answer:

None of the first four options are correct. The correct statement is: The gravity of a planet increases as its mass increases and its distance from the Sun decreases.