4.1 - 4.3 (openstax) Flashcards
dynamics
the forces that affect the motion of moving objects and systems
free-body diagram
a visualization that represents the object being acted upon—that is, the free body—as a single point and the external forces by vectors (arrows)
external force
a force that acts on an object within the system from outside the system
net external force
the total combined external force
force
the cause of motion
net force
the sum of all the forces acting on an object
friction
an external force that acts opposite to the direction of motion
mass
a measure of the amount of matter in an object; also a measure of the inertia of an object (its resistance to changes in acceleration)
inertia
the tendency for an object at rest to remain at rest, or for a moving object to remain in motion in a straight line with constant speed
newton’s first law of motion
- A body at rest tends to remain at rest.
- A body in motion tends to remain in motion at a constant velocity unless acted on by a net external force. (Recall that constant velocity means that the body moves in a straight line and at a constant speed.)
law of inertia
another name for newton’s first law of motion
system
one or more objects that you choose to study
freefall
when the net external force on an object is its weight
newton’s second law of motion
states how force causes change in motion,
𝐅net=𝑚𝐚 or Σ𝐅=𝑚𝐚
weight
the gravitational force of an object
