All Flashcards
Define Newton's Third Law.
For every action, there is an equal and opposite reaction.
What is an internal force?
A force between objects within a system.
What is an external force?
A force between an object in the system and something outside the system.
Define tension.
The pulling force transmitted through a string, cable, or similar object when it's pulled tight.
What is an ideal pulley?
A simple machine that changes the direction of a tension force.
What is the effect of pushing on a wall?
The wall exerts an equal and opposite force back on you.
What happens when internal forces act within a system?
The motion of the system's center of mass does not change.
What happens when an external force acts on a system?
The motion of the system's center of mass changes.
What is the effect of pulling on an ideal string?
Tension is created uniformly throughout the string.
What is the effect of pulling on a non-ideal string?
Tension is created, but it is not uniform throughout the string; it is greater at the top.
What are the differences between internal and external forces?
Internal Forces: Act within the system, do not affect the center of mass motion. | External Forces: Act on the system from outside, do affect the center of mass motion.
Compare real and ideal strings.
Ideal Strings: Negligible mass, inelastic, constant tension. | Real Strings: Have mass, can stretch, tension may vary.