While at a museum visit, Clara, Luis and Cami learned that the planet Venus is called Earth's sister. This is because it is similar in size to Earth. They also learned about different types of forces acting on the planets. At the end of the field trip, they were presented with an interactive table that compared the gravitational forces that were calculated between different objects and each of the two planets, Earth and Venus.

Question

While at a museum visit, Clara, Luis and Cami learned that the planet Venus is called Earth's sister. This is because it is similar in size to Earth. They also learned about different types of forces acting on the planets. At the end of the field trip, they were presented with an interactive table that compared the gravitational forces that were calculated between different objects and each of the two planets, Earth and Venus.
The museum guide asked the class, "What causes the differences in gravitational force of objects with the same mass on Venus and Earth?"
Clara, Luis and Cami each made a claim.
Clara: "Objects will feel a greater gravitational force on Earth, because Earth has more mass than Venus."
Luis: "Objects will feel the same gravitational force on Venus and Earth."
Cami: "Objects will feel a greater gravitational force on Venus, because Venus has less mass than Earth."

GPT-4o mini · Answer

The statements made by Clara, Luis, and Cami reflect misunderstandings about gravitational force and the factors that affect it. Let's break down each claim and clarify the correct reasoning.

Clara's Claim: "Objects will feel a greater gravitational force on Earth, because Earth has more mass than Venus."
- Analysis: Clara is partially correct about Earth having more mass than Venus; however, the gravitational force experienced by an object is not solely determined by the mass of the planet. The gravitational force also depends on the distance from the center of the planet (which is roughly the same for objects on the surfaces of both planets) as well as the gravitational constant. Earth's greater mass does indeed result in a stronger gravitational pull compared to Venus.
Luis's Claim: "Objects will feel the same gravitational force on Venus and Earth."
- Analysis: Luis's statement is incorrect. Objects on Venus experience a different gravitational force than those on Earth. This is due to the differences in the surface gravity of the two planets. While the exact gravitational force varies depending on the object's mass, the gravitational acceleration on Venus is about 90% that of Earth's; thus, objects will feel slightly less force on Venus.
Cami's Claim: "Objects will feel a greater gravitational force on Venus, because Venus has less mass than Earth."
- Analysis: Cami's claim is incorrect. Although Venus is indeed less massive than Earth, this does not lead to a greater gravitational force. In fact, the gravitational force on an object on Venus is less than that on Earth, again due to the differences in the gravitational acceleration experienced on each planet.

Conclusion: The difference in gravitational force experienced by an object of the same mass on Earth versus Venus primarily arises from the difference in surface gravity, which is influenced by the mass of the planets and their radii. Objects will exert a greater gravitational force on Earth as compared to Venus. The correct understanding is that, although Venus is similar in size to Earth, it has a lower mass and therefore exerts less gravitational pull on objects.