Chapter 5: Force & Motion I Flashcards
What is dynamics?
It is the study of the cause of motion.
What is a force?
An interaction between an agent (exerts the force) and an object (experiences the force) that can change the object’s velocity.
SI unit: newton (N).
Is force a vector quantity?
Yes!
What is mass?
A measure of a particle’s inertia.
SI unit: kilogram (kg)
Is mass a vector quantity?
No!
What is inertia?
The tendency to resist change in velocity.
What is Newton’s First Law of motion?
If the net force acting on an object is equal to zero, then the object’s velocity cannot change.
What is Newton’s Second law of motion?
A cause-and-effect relationship. When a net force acts on an object of mass m, then the object will accelerate. a = (Fnet)/m
What is Newton’s Third Law of motion?
If two particles, A and B, interact, then the force on A due to B and the force on B due to A have equal magnitudes but opposite directions.
What is an inertial reference frame?
Any reference frame in which Newton’s first law is valid.
Any reference frame fixed to Earth is (approximately) ___.
Inertial
Any reference frame moving at a constant velocity relative to Earth is (approximately) ___.
Inertial
Any reference frame accelerating relative to Earth is ___.
Non-inertial
What is force due to gravity?
The force acting on a particle due to its gravitational interaction with the nearest astronomical body. |Fgrav| = mg
___ is the gravitational field strength of an astronomical body.
g
On Earth, g = …
9.8 N/kg
While mass is a scalar quantity that is the same everywhere, weight is…
The magnitude of a vector quantity (mg) that depends on the local value of g.
What is tension force?
The force a taut rope exerts on any object to which it is attached.
There (is)/(is not) a specific mathematical formula for tension force.
There is not–it must be found using Newton’s second law.
What is normal force?
A reaction to two surfaces in contact. Just like tension force, there is no specific formula for it.
A normal force acts ___ to a surface.
Perpendicular
Newton’s third law is ALWAYS referring to two particles, and is true regardless of ___.
The relative size/masses of the two particles.
When a particle is in ___, it has no acceleration.
Equilibrium
