All Flashcards
What are the key differences between internal and external forces?
Internal forces: Act within a system, do not affect center of mass motion. | External forces: Act on the system from outside, do affect center of mass motion.
Differentiate between real and ideal strings regarding tension.
Ideal strings: Tension is constant throughout. | Real strings: Tension can vary due to the string's weight.
Define Newton's Third Law.
For every action, there is an equal and opposite reaction.
Define 'action-reaction pair'.
A pair of forces equal in magnitude, opposite in direction, acting on different objects.
What is an internal force?
Forces between objects within a system.
What is an external force?
Forces exerted on a system by objects outside the system.
Define 'center of mass (COM)'.
The point where all the system's mass can be considered concentrated.
What is tension?
The force transmitted along the length of a string, cable, or similar object.
Define an 'ideal string'.
A string with negligible mass that does not stretch.
Define an 'ideal pulley'.
A pulley with negligible mass and no friction.
What is the effect of an external force on a system's center of mass?
It changes the motion of the center of mass.
What is the effect of the weight of a real string on the tension?
The weight causes the tension to vary along the length of the string.