·
note that I horsepower up At highest point KE 0 =
is equivalent to 76W At lowest point U 0 =
when
buying electricity , you are
charged by the kilowatt-hour.
Section 6 .
1
potential energy is energy that is "stored" in an object by a force.
·
it is related to work by
VAB = -
WAB
·
we can define quavitational potential energy energy (GPE) as
AUgrav migh =
here , his change in height
This V; to value reference location where U = 0
is
change in
get at location
,
we need to choose a
arbitrary ; only Du , not v has physical meaning.
regardless of choice of where U 0 =
,
the changes inV between
heights are same
·
we choose a convenient location for U = 0 = U =0 ,
based on problem ·
* choose the lowest height.
·
For GPE horizontal ,
motion has no effect (no gravitational Force)
Section 6 2 .
·
if UA UB=
,
the
Wgvav , AB
=
0
this means that gravity is a conservative force ,
one for which work done
around is
a closed path displacement = o zero.
a nonconservative force does a non-zero amount of work on object that moves around a closed path
for a conservative force , path taken from point A to B doesnt matter ; only the endpoints
themselves matters.
Friction
Kinetic friction always acts opposite to the motion so angle between His displacement is 1800 ,
·
,
and Wp =
-fic(DX)
=> Wr + 0 around closed path , and ty is non-conservative .
note that I horsepower up At highest point KE 0 =
is equivalent to 76W At lowest point U 0 =
when
buying electricity , you are
charged by the kilowatt-hour.
Section 6 .
1
potential energy is energy that is "stored" in an object by a force.
·
it is related to work by
VAB = -
WAB
·
we can define quavitational potential energy energy (GPE) as
AUgrav migh =
here , his change in height
This V; to value reference location where U = 0
is
change in
get at location
,
we need to choose a
arbitrary ; only Du , not v has physical meaning.
regardless of choice of where U 0 =
,
the changes inV between
heights are same
·
we choose a convenient location for U = 0 = U =0 ,
based on problem ·
* choose the lowest height.
·
For GPE horizontal ,
motion has no effect (no gravitational Force)
Section 6 2 .
·
if UA UB=
,
the
Wgvav , AB
=
0
this means that gravity is a conservative force ,
one for which work done
around is
a closed path displacement = o zero.
a nonconservative force does a non-zero amount of work on object that moves around a closed path
for a conservative force , path taken from point A to B doesnt matter ; only the endpoints
themselves matters.
Friction
Kinetic friction always acts opposite to the motion so angle between His displacement is 1800 ,
·
,
and Wp =
-fic(DX)
=> Wr + 0 around closed path , and ty is non-conservative .
