Can somebody pls explain this to me?
The earth is exerting a force on the object in free fall. The object is exerting an equal and opposite force on the earth. As there is only the one force on the object, it is accelerating as it falls. The earth is also accelerating, but with a much smaller magnitude.However, given that the normal force is a contact force, what would be the force opposed to weight in the case of free fall?
That is true, as with any force.As far as I've understood from my physics lectures, the normal force is a contact force which arises as a reaction of another force (third Newton's law)
No, that is wrong. Well, ultimately, it is true but you are seeing those two forces as a Newton's third law pair and that is wrong. As Pixel said, the Newton's 3rd law pair of gravity exerted by the earth on an object (1) is gravity exerted by the object on the earth (2). That is so when the object is in free fall and also when it is at rest on the ground. But in the latter case (object resting on the ground), there is also another pair of forces involved: contact force exerted by the object on the earth (3) and contact force exerted by the earth on the object (4).For example, in the case of weight, the earth exerts a force (mg) on us and so we exert a force on the Earth (i.e. the normal force).
You do realize that this thread is over 2 1/2 years old, and the OP hasn't visited Physics Forums for about 2 years, right? I'm closing this thread.