Mainly Gravity...
The boy is jumping up, which is inertia, but gravity is much stronger.
As soon as he's free of the chair and out in 'space', the boy begins accelerating toward the Earth, and the Earth begins accelerating toward the boy, because of the equal, mutual forces of gravitation that attract them to each other.
gravity
The force that pulls an object toward earth also pulls the earth toward the object. The two forces are equal. Together, we refer to them as the force of gravity.
The force that pulls an object toward earth also pulls the earth toward the object.The two forces are equal. Together, we refer to them as the force of gravity.
The force that pulls an object toward earth also pulls the earth toward the object.The two forces are equal. Together, we refer to them as the force of gravity.
The force that pulls an object toward earth also pulls the earth toward the object.The two forces are equal. Together, we refer to them as the force of gravity.
The force of gravitation attracting the earth and moon toward each other is exactly the same force on both bodies.Just as the force of gravitation that attracts you toward the earth is exactly the same as the force that attractsthe earth toward you.
The force that pulls an object toward earth also pulls the earth toward the object. The two forces are equal. Together, we refer to them as the force of gravity.
The force that pulls an object toward earth also pulls the earth toward the object. The two forces are equal. Together, we refer to them as the forces of gravity.
We are staying on the surface after jumping instead of flying off forever until we come to another gravitational object.
Gravity causes a 'mutual' force between every two masses, that attracts each of them toward the other one. The mutual force between the sun and earth is what keeps the earth in its orbit around the sun.
The force of gravity that attracts an object on Earth toward the Earth is the object's weight on Earth. The force of gravity that attracts the Earth toward an object on it is the Earth's weight on the object. Both forces are always there, and they're equal.