All Flashcards
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.
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.
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.