Difference between External Force and Internal Force
External and internal forces are fundamental concepts in physics that describe interactions in a system. Here’s a detailed breakdown:
External Force
- External forces are influences that originate from outside a system.
- They can change the motion of an object or cause deformation.
- Examples include gravitational force, friction, and applied forces (like pushing or pulling).
- External forces can be seen as agents that interact with a system, leading to acceleration and movement.
- They are responsible for initiating or altering the state of motion of objects within the system.
Internal Force
- Internal forces are the interactions that occur within a system itself.
- These forces do not change the motion of the center of mass of the system as a whole.
- Examples include tension in a rope, compression in a spring, or molecular forces within a material.
- Internal forces are equal and opposite according to Newton's third law (action-reaction).
- While they can cause changes in the shape or structure of the system, they do not contribute to the overall motion of the system.
Key Differences
- Source: External forces come from outside the system, while internal forces originate from components within the system.
- Effect on Motion: External forces can change the velocity of a system, whereas internal forces do not affect the overall motion of the system.
- Examples: External forces include gravity and friction; internal forces include tension and compression.
Understanding these differences is crucial in fields like mechanics, engineering, and material science, as they influence how systems respond to various conditions.