Physics (Midterms - Concepts) Flashcards
describes the relationship between the motion of objects in our everyday world and the forces acting on them
dynamics
Language of Dynamics
Force and Mass
the measure of interaction between two objects (pull or push). It is a vector quantity - it has a magnitude and direction
force
the measure of how difficult it is to change object’s velocity (sluggishness or inertia of the object)
mass
may be a contact force or field force
forces
it result from physical contact between two objects
contact forces
it act between disconnected objects and it is also called as “action at a distance”
field forces
Forces
gravitational force
archimedes force
friction force
tension force
spring force
normal force
a resultant force acting on object
net force
an object at rest tends to stay at rest and an object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force
newton’s first law
it is defined as the vector sum of all the external forces exerted on the object
net force
is a property of objects to resist changes in motion
inertia
is a measure of the amount of inertia
mass
is a measure of the resistance of an objects to changes in its velocity
mass
is an inherent property of an object
mass
the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass
newton’s second law
also measured in lbs, is a force (mass x acceleration)
weight
the magnitude of the gravitational force acting on an object of mass m near the earth’s surface is called the
weight
it can also be found from the law of universal gravitation
g
it has a unit of N
weight
force from a solid surface which keeps object from falling through
normal force
its direction is always perpendicular to the surface
normal force
it direction is pointing downward
gravitational force
a taut rope exerts forces on whatever holds its ends
tension force
its direction is always along the cord (rope, cable, string,…) and away from the object
tension force
if object 1 and object 2 interact, the force exerted by object 1 on object 2 is equal in magnitude but opposite in direction to the force exerted by object 2 on object 1
newton’s third law
either force can be the action or reaction force
newton’s third law
the most important step in solving problems involving Newton’s laws
free body diagram
objects that are either at rest or moving with constant velocity are said to be in equilirbium
objects in equilibrium
if an object that can be modeled as a particle experiences an acceleration, there must be a non-zero net force acting on it
accelerating objects
4 basic quantities in kinematics
displacement
velocity
time
acceleration
any motion involves three concepts
displacement
velocity
acceleration
it can be defined as the change of position over time
motion
is a change of position in time
displacement
it is a vector quantity. it has both magnitude and direction and it has units of length in meters
displacement
rate of change of position
velocity
it is a vector quantity. it has both magnitude and direction. it has a length/time in meter per second1
velocity
is the slope of the line segment between end points on a graph
average velocity
total distance over time interval
average speed
it means “at some given instant”
instantaneous
it indicated what is happening at every point of time
instantaneous velocity
is the special case of constant velocity
uniform velocity
it means “an acceleration is present”
changing velocity or non-uniform
rate of change of velocity
acceleration