Forces from a distance

The idea

Forces whose effect can be experienced even when the objects are not in contact are called non-contact forces.

Not touching

You do not always have to touch an object to make it move.

Can a force act on an object that it is not touching?

• Yes, some forces can
• No, never
• Only if there is a rope

Bring it closer

Slide the clip closer to the magnet. Watch what happens before they touch.

The pull came first

The clip was pulled to the magnet before the two touched. Some forces can be experienced even when the objects are not in contact.

Forces whose effect can be experienced even when the objects are not in contact are called non-contact forces.

Notes

Forces whose effect can be felt even when the objects are not in contact are non-contact forces.

Check yourself

Forces that work even when objects are not in contact are …

Which of these is a non-contact force?

A magnet pulls an iron clip lying a little away from it. This shows that the force …

Is muscular force a non-contact force?

• contact forces. Contact forces act only when the objects touch.
• non-contact forces — correct. Yes!
• muscular forces. Muscular force is a contact force.
• Pushing a box with your hand. Your hand touches the box. That is a contact force.
• Pulling a cart with a rope. The rope touches the cart. That is a contact force.
• A magnet pulling a clip from a distance — correct. Yes!
• acts without contact — correct. Yes!
• needs contact. The clip is not in contact with the magnet, yet it is pulled.
• is friction. Friction needs two surfaces in contact. This force does not.
• Yes, always. Muscular force needs contact, direct or indirect.
• No, it is a contact force — correct. Yes!
• Yes, if the muscles are strong. Muscular force is a contact force whatever the strength.