By size I think you mean the volume. And no, you also need the density of the object. Which tells you how much a given size weighs.
The mass of the two objects and the distance between their centres of gravity.
the mass of the objects and the distance of the objects
Mass, speed.
The mass of the objects and the distance between them.
The only "weigh" to determine the mass of an object is to compare it with the mass of a known object. The mass of an object is determined by force and acceleration.
The mass of the two objects and the distance between their centres of gravity.
the mass of the objects and the distance of the objects
mass
the size
But you CAN determine the size of the planets: in diameter, overall mass, and in density.
Mass, speed.
Determine its mass on a balance. Determine its volume using water displacement. Divide the mass by the volume.
Determine its mass on a balance. Determine its volume using water displacement. Divide the mass by the volume.
The mass of the objects and the distance between them.
mass and volume
The mass of the objects and the distance between the two objects.
The only "weigh" to determine the mass of an object is to compare it with the mass of a known object. The mass of an object is determined by force and acceleration.