Forces can cause changes in an object's motion or form. A contact force requires direct contact between objects, like frictional or muscular forces, while a non-contact force acts over a distance without touching, such as gravitational, magnetic, or nuclear forces. Forces are interactions that can change the motion of an object when unopposed.

2. FORCE
• A force is any interaction that, when
unopposed, will change the motion of
an object.
• Force can cause change in motion of a body.
• Force can cause change in form of a body.

3. CONTACT FORCE
• A force is seen to act through a direct
contact of the objects or via one more
object such a force is called ‘Contact
force’.
• Contact is must in this case.

4. CONTACT FORCES IN
NATURE
•Frictional force
•Punching action
•Muscular force

5. NON-CONTACT FORCE
• A force is applied between two objects
even if the two objects are not in
contact; such a force is called a ‘Non
contact force’.
• No contact is required in this case.

6. NON-CONTACT
FORCES IN NATURE
• Gravitational Force
• Magnetic Force
• Nuclear Force
• Attraction & Repulsion