Final answer:
An object on Jupiter weighs only about three times more than on Earth due to Jupiter's large size and low density, which cause a lower surface gravity compared to what its mass would suggest. Additionally, Jupiter's rapid rotation creates centrifugal force that further reduces the effective gravity experienced on its surface.
Step-by-step explanation:
The explanation of why an object on Jupiter weighs only about three times as much as it would on Earth, despite Jupiter having more than 300 times the mass of Earth, lies in Jupiter's enormous size and lower density. Jupiter's diameter is roughly 11 times greater than Earth's and its volume is so expansive that it could fit more than 1,300 Earths inside. Consequently, an object on Jupiter's surface is much farther away from the planet's center compared to its distance from Earth's center when it's on Earth's surface. This distance reduces the gravity's pull despite Jupiter's large mass. Additionally, Jupiter's average density is about 1.3 g/cm³, which is lower than Earth's density, meaning its mass is spread over a larger volume.
Jupiter's gravitational pull is further mitigated by its rapid rotation. The giant planet has a short day, rotating once every 10 to 17 hours. This quick rotational speed causes a strong centrifugal force which works against the planet's gravitational pull, reducing the effective weight of an object on Jupiter's surface.