Gravitational force = G M₁ M₂ / R²
' G ' is 6.673 x 10⁻¹¹ m³ / kg - s²
In this particular problem,
M₁ is the mass of the Earth = 5.972 x 10²⁴ kg
M₂ is the mass of the wrestler = 1500 kg
' R ' is the distance between their centers. That's the radius of the Earth = 6,371 x 10³ meters
You can stuff all these numbers into the formula for gravitational force, like we did with the 60kg student and the 120kg door.
Or you can just say to yourself: "Self ! This problem is just looking for the wrestler's 'weight'. We know that's just (mass) x (acceleration of gravity). On Earth, the acceleration of gravity is 9.8 m/s². All I have to do is multiply that by his mass of 1500 kg and the answer will be his weight in Newtons."
When you do that, you get
Weight = (9.8 m/s²) x (1500 kg)
Weight = 14,700 Newtons (about 3,307 pounds !)
What happened here ? ? I know he's a Sumo wrestler and all, and they really like to eat. But 3,307 pounds ? ? ?
What happened is the "1500 kg". That can't be correct for a human being. It's more like a small elephant.
I'm pretty sure you mis-copied the problem, and his mass is actually 150kg.
