non-contact forces – any forces that occur between two objects that are physically separated (not touching)
Note: contrast this with contact forces.
There are four main non-contact forces:
Magnetic force - A force which acts between magnetic material or moving charges and can also attract or repel depending on the magnetic poles involved.
Electrostatic force - This acts between electrically charged objects and can either be attractive (between opposite charges) or repulsive (between like charges).
Gravitational force - A force that acts between any two masses and causes objects to attract each other (such as the Earth pulling objects downward or the Sun holding planets in orbit).
To remember the three main non-contact forces, use the following mnemonic:
The magnet was not allowed contact with anyone and was forced (magnetic force) into isolation after zapping me with an electrode. I was static (electrostatic force) and then fell to the ground due to gravity (gravitational force).
Non-contact forces are forces that can act on objects without the need for physical contact between them, meaning the objects can influence each other across a distance through force fields. Unlike contact forces such as friction, air resistance or tension that require objects to touch, non-contact forces operate through empty space and can affect objects separated by considerable distances.
Magnetic Force
A non-contact force is a force that acts without objects touching.
Magnets can attract or repel other magnets or magnetic materials from a distance, so they do not need to be in contact. This happens because magnets produce a magnetic field, and objects inside this field experience a force. If you bring two magnets close together:
- North and south poles attract.
- North and north (or south and south) repel.
They can move before they touch, showing the forces acts at a distance.
Electrostatic Force
An electrostatic force occurs between charged objects and they can attract or repel each other from a distance.
This happens because charged objects create an electric field around them. When another charged object enters this field, it experiences a force.
If you rub a balloon on your hair, the balloon becomes electrically charged. When you bring it near small pieces of paper, the paper moves towards the balloon without touching it first. This shows the force acts without contact.
Gravitational Force
Gravity pulls objects with mass towards each other even when they are not in contact. For example, the Earth pulls objects towards it, causing them to fall to the ground.
