Contact and Non-Contact Forces

• Forces change the motion of an object

Contact vs Non-Contact Forces

• A force is a push or pull on an object.
• Contact force occurs when one object pushes or pulls another by touching it, examples include pushing a container, pressing on computer keys, and friction.
• Non-Contact Force occurs when one object pushes or pulls another without touching it, examples include magnetic, electrical, and gravity.

Friction

• Friction is a force that resists the motion of two objects that are touching.
• Static friction prevents objects from sliding past each other.
• Sliding friction opposes the motion of objects sliding past each other.
• Fluid friction occurs between a surface and a fluid, like water or air (air resistance).

Gravity and Mass

• Gravity: An attractive force that exists between all objects that have mass
• Mass: Amount of matter in an object
• The more the mass, the more gravitational pull
• The greater the distance, the less gravitational pull
• Weight is the amount of gravitational force exerted on an object, measured in newtons.
• Weight would be less on the moon.

Static Charge

• Static Charge: Unbalanced positive or negative charge on an object.
• Opposite charges attract each other.
• The same charges repel each other.
• The more the charge, the greater the electrical force (attractive or repulsion).
• The more distance, the less electrical force.

Magnets

• Magnet: Object that attracts metal iron.
• Magnetic Pole: A place on a magnet where the force applied is the strongest.
• Opposite poles (charges) attract each other
• The same poles (charges) repel each other
• The further away the magnets are the weaker the magnetic force
• Magnetic strength depends on the size of the magnet.

Explore contact and non-contact forces like friction, gravity, and magnetic forces. Understand the differences between static, sliding, and fluid friction. Learn how mass and distance affect gravitational pull shaping our understanding of forces.