Since the position doesn't change over that time, it's zero
Magnetic fields can go through some materials (like cardboard). Electric fields can also do that. Electromagnetic waves can do that. It’s not at all unusual because magnetic fields are not made up of particles so they can go through materials.
The law of conservation of linear momentum says that when objects collide, the total initial momentum equals the total final momentum.
The momentum of a body is given by the product of mass and velocity of the object.
The 1kg ball would exert the smallest force.
As force = mass x gravity, this means that the smaller the mass (kg), the lesser the force.
When the mass is lighter (1kg):
Force = mass x gravity
Force = 1 x 9.8
Force = 9.8N
Compared to when the mass is heavier (10kg)
Force = mass x gravity
Force = 10 x 9.8
Force = 98N
Where this proves that the lighter the mass, the smaller the force exerted.