Final answer:
Friction is a resistive force opposing motion or its tendency. Simple friction is always proportional to the normal force. To distinguish whether the friction force depends on the weight of the object or the normal force, you can modify the experiment by changing the angle of the surface or by using objects with different weights on the same surface.
Step-by-step explanation:
Friction is a resistive force opposing motion or its tendency. When an object rests on a horizontal surface, the normal force supporting it is equal in magnitude to its weight. Simple friction is always proportional to the normal force.
If you want to distinguish whether the friction force depends on the weight of the object or the normal force, you can modify the experiment by changing the angle of the surface or by using objects with different weights on the same surface. By measuring the friction force in each case, you can then compare whether the friction force changes proportionally to the weight or the normal force.