Explain what the net force on an object will be if balanced forces act on it. what will happen to the net force if unbalanced forces act on an object?

If the forces on an object are balanced, then the sum of all their sizes and
directions (the net force) is zero, and their effect on the object is the same
as if there were no force acting on it at all.

If the forces on an object are not balanced, then the sum of all their sizes and
directions (the net force) is not zero.  Their effect on the object is the same as
if there were only a single force on it.  If you know the sizes and directions of
all the individual forces, then it's not hard to calculate the size and direction of
the equivalent single force that would have the same effect.

The net force of an object if balanced is zero, this is called static equilibrium, if the net force is unbalanced then it's in motion.

Bag of bolts weight 29.4n