What are Contact Forces?
Contact forces are forces that can be applied only when the interacting objects are in physical contact with each other.
1. Muscular Force
This force results from the action of muscles.
- Example: Lifting a bucket, kicking a ball, or a bullock pulling a cart.
- Mechanism: Muscles contract and relax to exert force on bones or objects. It is essential for all our physical activities and body functions (like digestion and blood circulation).
2. Friction
Have you noticed that a ball rolling on the ground eventually stops? This is due to Friction.
- Definition: The force that acts between two surfaces in contact and opposes the motion of one surface over the other.
- Direction: Friction always acts in the opposite direction to the motion.
- Cause: It arises due to irregularities (roughness) on the two surfaces locking into each other. Even smooth-looking surfaces have microscopic irregularities.
Warning
Rough vs. Smooth: Friction is greater on rough surfaces (like sand or carpet) and lesser on smooth surfaces (like ice or glass). This is why we slip on wet floors—water reduces friction!