Class One Flashcards
what are kinematics
description of motion in terms of an object’s position, velocity and acceleration
what is displacement
change in position of an object
what is velocity
tells us how fast an object’s position changes
velocity formula
displacement / time
speed is the..
magnitude of the velocity vector
characteristics of speed
has no direct & can never be negative
characteristics of velocity
specifies speed and direction
what is acceleration
how fast an object’s velocity changes
acceleration formula
change in velocity / time
if acceleration points in the same direction as initial velocity..
speed is increasing
if acceleration points in the direction opposite to initial velocity..
the speed is decreasing
what is uniformly accelerated motion
when an object’s acceleration is constant
slope of a position vs time graph gives..
velocity
slope of a velocity vs time graph gives..
acceleration
the area under a velocity vs time graph gives..
the displacement
what is free fall
an object moving only under the influence of gravity
gravitational acceleration
10 m/s2
free fall acceleration and mass
the free fall acceleration of an object does not depend on its mass
2 objects would fall at the same time
what is projectile motion
constant, downward acceleration due to gravity
what is constant in projectile motion
horizontal motion velocity
at the top of the parabola for projectile motion..
vertical velocity is 0
symmetry of a parabola of projectile motion means..
the projectile’s total flight time will be twice the time required to reach the top
horizontal displacement is also called..
range
what is a force
a push/pull exerted by one object on another
Newton’s first law
an object’s velocity will not change unless a net force acts on it
no net force = no acceleration
what is inertia
object’s natural resistance to change in their state of motion
Newton’s first law is also known as..
the law of inertia
Newton’s second law
Fnet = ma
total force on an object = mass of object x acceleration
what is force is not included in Fnet
forces exerted BY the object
mass of object = positive so..
the direction of acceleration is always the same direction of Fnet
Newton’s third law
the forces in an action-reaction pair have the same magnitude and act in opposite directions
**does not say that the effects of the forces will be the same
weight vs mass
weight: gravitational force exerted on an object
mass: intrinsic property of an object
Newton’s Law of Gravitation
the magnitude of the gravitational force the universe exerts on an on object is proportional to the product of the object’s masses and inversely proportional to the square of the distance between them
Law of Gravitation formula
what is friction
electrical attraction between atoms of one surface with those of another
+
roughness of surfaces
categories of friction
static & kinetic (sliding) friction
what is static friction
when there is no relative motion between the surfaces that are in contract (no sliding)
what is kinetic friction
when there is relative motion between the surfaces
what is normal force
the perpendicular component of the contact force exerted by a surface on an object
force of kinetic friction formula
the direction of the force of kinetic friction is always..
parallel to the surface
opposite direction to the object’s velocity
the direction of the force of kinetic friction is always..
parallel to the surface
opposite direction to the object’s velocity
the maximum coefficient of static force is always..
greater than the coefficient of kinetic force
why is there only a maximum force of static friction formula
static friction is capable of supplying necessary force, but only up to a certain maximum
the force due to gravity acting parallel to the inclined plane =
mg(sin∅)
the force due to gravity acting perpendicular to the inclined plane =
mg(cos∅)
what is a pulley
a device that changes the direction of tension that pulls on the object that the string is attached to
