SCI206 Lecture Notes - Lecture 3: Normal Force
21 Oct 2016
School
Department
Course
Professor
!"#$%&'()*+,-,
./(01(-%2(31(4%&"5
6/(.11(4%&"5
7(892:(%&(-9;%9&(;,&2<(;9(#,-"%&(%&(-9;%9&
○
=&,#;%"(2,>,&2<(9&(-"<<
§
7(892:(";(#,<;(;,&2<(;9(#,-"%&(";(#,<;
○
Inertia(
-
?9<%;%9&(%<(2,<*#%8,2(@%;+("(vectorA(2%#,*;%9&("&2(2%<;"&*,
○
B,59*%;:(C<>,,2("&2(2%#,*;%9&
○
)>,,2%&'(D>A(<59@%&'(29@&A(*+"&'%&'(2%#,*;%9&
§
7**,5,#";%9&(CE9@(4"<;(F,59*%;:(%<(*+"&'%&'
○
Describing(Motion
-
G%#<;(5"@/(7&(98H,*;(&9;(<D8H,*;(;9(9D;<%2,(49#*,<(-9F,<(";(*9&<;"&;(F,59*%;:A(*9F,#%&'(
,ID"5(2%<;"&*,<(%&(,ID"5(;%-,<(J%&,#;%"K
○
L"<%,#(;9(-9F,("(5%'+;(98H,*;(;+"&("(+,"F%,#(9&,
M
LN"->5,/(45%*$%&'(;+,(>%&'>9&'(8"55(F<(45%*$%&'("(8"<,8"55(
M
G(O(-"
§
),*9&2(5"@/(P+,(49#*,(,N,#;,2( 9&("&(98H,*;(%<(,ID"5(;9(;+,(>#92D*;(94(;+,(98H,*;Q<(
-"<<(;%-,<(%;<("**,5,#";%9&R(P+,("**,5,#";%9&( %<(;+,(<"-,(2%#,*;%9&("<(;+,(49#*,
○
7S)TA(;+,(>,&*%5(;%>(%<('9%&'(;9(8#,"$(J,ID"5("&2(9>>9<%;,(#,"*;%9&K
M
L'(H"88%&'("(>,&*%5(%&;9(:9D#(+"&2(%<('9&&"(+D#;
§
P+,:Q#,('9%&'(;9('9(%&;9(9>>9<%;,(2%#,*;%9&<
M
L'(85D,(*"#(>D<+%&'(#,2(*"#
§
P+%#2(5"@/(G9#(,F,#:(49#*,(;+";(9&,(98H,*;(,N,#;<(9&("(<,*9&2(98H,*;A(;+,#,(%<("&(,ID"5(
8D;(9>>9<%;,5:(2%#,*;,2(49#*,(;+";(;+,(<,*9&2(98H,*;(,N,#;<(9&(;+,(4%#<;(98H,*;
○
Newton's(Laws
-
G(O(-'(J'(O('#"F%;:K
○
U9#-"5(49#*,(4#9-('#9D&2(>D<+,<(D>(9&(8"#8%,
○
GJ;9;"5K(O(U(CG(O(1(J8"#8%,(29,<&V;(-9F,K
○
W,%'+;("**9D&;<(49#('#"F%;:
§
!"<<(@%55(8,(;+,(<"-,(9&(;+,(-99&
§
W,%'+;(OXO(-"<<
○
P+,(<%2,(@%;+(;+,(-99&(%<(";;#"*;,2(8:(-99&Q<('#"F%;:("&2(;+,(9>>9<%;,(<%2,(+"<(
5,<<('#"F%;:(;+D<(89;+(<%2,<(+"F,("(+%'+(;%2,
§
E%'+(;%2,(%<(8,*"D<,(94('#"F%;:
○
Gravity
-
G(O(-'(O(-"
○
'(O("
○
7**,5,#";%9&(%<(%&2,>,&2,&;(94(-"<<
○
LN"->5,(94(4,";+,#("&2(*9%&(%&<%2,(F"**D-
§
G,";+,#(@%55(4"55("<(4"<;("<("(5,"2(8#%*$(J%'&9#%&'(@%&2(#,<%<;"&*,K
○
7**,5,#";%9&(J'#"F%;:K((%<(*9&<;"&;A(-"<<(%<(*9&<;"&;A(&9;+%&'(%<(*+"&',2(8,*"D<,(
;+,(49#*,(%<(;+,(<"-,
§
Y:(;9<<%&'("(8"55(D>@"#2<
○
=4(;+,(*"#;(%<(;#"F,55%&'(9&("(;#"*$("&2(;+,(8"55(%<(;9<<,2(D>@"#2<A(%;Q55(5"&2(8"*$(
%&;9(;+,(*"#;
§
Z"#;(@%;+(8"55(,N"->5,
○
L'(&,#4('D&(<+9;
§
G"55%&'(8"55<(+"F,("(>"#"895%*(>";+
○
7<<D-%&'(;+,(-9&$,:(4"55<(#%'+;(@+,&(;+,(8D55,;(%<(<+9;A(:9D("%-(";(;+,(-9&$,:
§
P+%<(%<(8,*"D<,('#"F%;:("44,*;<(89;+(98H,*;<(;+,(<"-,A(<9(;+,:Q55(89;+(4"55(";(;+,(
<"-,(#";,(,&<D#%&'("(+%;
§
J%,(;+,(+9#%[9&;"5(49#*,(-"$,<(&9(2%44,#,&*,K
§
Y"55('D&(<+99;%&'(";(-9&$,:
○
Falling(Ball
-
Energy
-
P+,(-9#,(-"<<A(;+,(-9#,('#"F%;";%9&"5(>9;,&;%"5(,&,#':(%;(+"<(J*"&9&8"55(F<(8"<,8"55K(
○
P+,(+%'+,#A(;+,(-9#,('#"F%;";%9&"5(>9;,&;%"5(,&,#':
○
L&,#':(O(>9;,&;%"5(,&,#':(\($%&,;%*(,&,#':
○
W9#$(O(49#*,(](2%<;"&*,
○
W9#$(O(-'+
○
=4(:9D(+"F,("(*"&&9&8"55(9#(>%&'>9&'(8"55("&2(:9D(@"5$("#9D&2(%;A(;+,(@9#$(9&(
;+,(6(98H,*;<("#,(;+,(<"-,(J2%<;"&*,("&2(49#*,("#&,;(*+"&'%&'K
§
=4(:9D("#,(&9;(>D<+%&'(9#(%;<(&9;(-9F%&'A(;+,&(:9D("#,&;(@9#$%&'
○
Work
-
P,&2,&*:(;9(*9&;%&D,(-9F%&'(%&("(*,#;"%&(2%#,*;%9&
○
!9#,(-9-,&;D-/(;,&2(;9(@%&2(*955%<%9&<
○
!9-,&;D-(O(!"<<(](B,59*%;:
○
!9#,(-"<<(O(!9#,(-9-,&;D-
○
^9D(@9&;(4,,5("&:;+%&'(%&("(8D<(*#"<+
§
!9#,(F,59*%;:(O(!9#,(-9-,&;D-
○
Momentum
-
○
!9&2":A(.6(),>;,-8,#( 61.3
_/`6(?!
!"#$%&'()*+,-,
./(01(-%2(31(4%&"5
6/(.11(4%&"5
7(892:(%&(-9;%9&(;,&2<(;9(#,-"%&(%&(-9;%9&
○
=&,#;%"(2,>,&2<(9&(-"<<
§
7(892:(";(#,<;(;,&2<(;9(#,-"%&(";(#,<;
○
Inertia(
-
?9<%;%9&(%<(2,<*#%8,2(@%;+("(vectorA(2%#,*;%9&("&2(2%<;"&*,
○
B,59*%;:(C<>,,2("&2(2%#,*;%9&
○
)>,,2%&'(D>A(<59@%&'(29@&A(*+"&'%&'(2%#,*;%9&
§
7**,5,#";%9&(CE9@(4"<;(F,59*%;:(%<(*+"&'%&'
○
Describing(Motion
-
G%#<;(5"@/(7&(98H,*;(&9;(<D8H,*;(;9(9D;<%2,(49#*,<(-9F,<(";(*9&<;"&;(F,59*%;:A(*9F,#%&'(
,ID"5(2%<;"&*,<(%&(,ID"5(;%-,<(J%&,#;%"K
○
L"<%,#(;9(-9F,("(5%'+;(98H,*;(;+"&("(+,"F%,#(9&,M
LN"->5,/(45%*$%&'(;+,(>%&'>9&'(8"55(F<(45%*$%&'("(8"<,8"55(M
G(O(-"
§
),*9&2(5"@/(P+,(49#*,(,N,#;,2( 9&("&(98H,*;(%<(,ID"5(;9(;+,(>#92D*;(94(;+,(98H,*;Q<(
-"<<(;%-,<(%;<("**,5,#";%9&R(P+,("**,5,#";%9&( %<(;+,(<"-,(2%#,*;%9&("<(;+,(49#*,
○
7S)TA(;+,(>,&*%5(;%>(%<('9%&'(;9(8#,"$(J,ID"5("&2(9>>9<%;,(#,"*;%9&K
M
L'(H"88%&'("(>,&*%5(%&;9(:9D#(+"&2(%<('9&&"(+D#;
§
P+,:Q#,('9%&'(;9('9(%&;9(9>>9<%;,(2%#,*;%9&<M
L'(85D,(*"#(>D<+%&'(#,2(*"#
§
P+%#2(5"@/(G9#(,F,#:(49#*,(;+";(9&,(98H,*;(,N,#;<(9&("(<,*9&2(98H,*;A(;+,#,(%<("&(,ID"5(
8D;(9>>9<%;,5:(2%#,*;,2(49#*,(;+";(;+,(<,*9&2(98H,*;(,N,#;<(9&(;+,(4%#<;(98H,*;
○
Newton's(Laws
-
G(O(-'(J'(O('#"F%;:K
○
U9#-"5(49#*,(4#9-('#9D&2(>D<+,<(D>(9&(8"#8%,
○
GJ;9;"5K(O(U(CG(O(1(J8"#8%,(29,<&V;(-9F,K
○
W,%'+;("**9D&;<(49#('#"F%;:
§
!"<<(@%55(8,(;+,(<"-,(9&(;+,(-99&
§
W,%'+;(OXO(-"<<
○
P+,(<%2,(@%;+(;+,(-99&(%<(";;#"*;,2(8:(-99&Q<('#"F%;:("&2(;+,(9>>9<%;,(<%2,(+"<(
5,<<('#"F%;:(;+D<(89;+(<%2,<(+"F,("(+%'+(;%2,
§
E%'+(;%2,(%<(8,*"D<,(94('#"F%;:
○
Gravity
-
G(O(-'(O(-"
○
'(O("
○
7**,5,#";%9&(%<(%&2,>,&2,&;(94(-"<<
○
LN"->5,(94(4,";+,#("&2(*9%&(%&<%2,(F"**D-
§
G,";+,#(@%55(4"55("<(4"<;("<("(5,"2(8#%*$(J%'&9#%&'(@%&2(#,<%<;"&*,K
○
7**,5,#";%9&(J'#"F%;:K((%<(*9&<;"&;A(-"<<(%<(*9&<;"&;A(&9;+%&'(%<(*+"&',2(8,*"D<,(
;+,(49#*,(%<(;+,(<"-,
§
Y:(;9<<%&'("(8"55(D>@"#2<
○
=4(;+,(*"#;(%<(;#"F,55%&'(9&("(;#"*$("&2(;+,(8"55(%<(;9<<,2(D>@"#2<A(%;Q55(5"&2(8"*$(
%&;9(;+,(*"#;
§
Z"#;(@%;+(8"55(,N"->5,
○
L'(&,#4('D&(<+9;
§
G"55%&'(8"55<(+"F,("(>"#"895%*(>";+
○
7<<D-%&'(;+,(-9&$,:(4"55<(#%'+;(@+,&(;+,(8D55,;(%<(<+9;A(:9D("%-(";(;+,(-9&$,:
§
P+%<(%<(8,*"D<,('#"F%;:("44,*;<(89;+(98H,*;<(;+,(<"-,A(<9(;+,:Q55(89;+(4"55(";(;+,(
<"-,(#";,(,&<D#%&'("(+%;
§
J%,(;+,(+9#%[9&;"5(49#*,(-"$,<(&9(2%44,#,&*,K
§
Y"55('D&(<+99;%&'(";(-9&$,:
○
Falling(Ball
-
Energy
-
P+,(-9#,(-"<<A(;+,(-9#,('#"F%;";%9&"5(>9;,&;%"5(,&,#':(%;(+"<(J*"&9&8"55(F<(8"<,8"55K(
○
P+,(+%'+,#A(;+,(-9#,('#"F%;";%9&"5(>9;,&;%"5(,&,#':
○
L&,#':(O(>9;,&;%"5(,&,#':(\($%&,;%*(,&,#':
○
W9#$(O(49#*,(](2%<;"&*,
○
W9#$(O(-'+
○
=4(:9D(+"F,("(*"&&9&8"55(9#(>%&'>9&'(8"55("&2(:9D(@"5$("#9D&2(%;A(;+,(@9#$(9&(
;+,(6(98H,*;<("#,(;+,(<"-,(J2%<;"&*,("&2(49#*,("#&,;(*+"&'%&'K
§
=4(:9D("#,(&9;(>D<+%&'(9#(%;<(&9;(-9F%&'A(;+,&(:9D("#,&;(@9#$%&'
○
Work
-
P,&2,&*:(;9(*9&;%&D,(-9F%&'(%&("(*,#;"%&(2%#,*;%9&
○
!9#,(-9-,&;D-/(;,&2(;9(@%&2(*955%<%9&<
○
!9-,&;D-(O(!"<<(](B,59*%;:
○
!9#,(-"<<(O(!9#,(-9-,&;D-
○
^9D(@9&;(4,,5("&:;+%&'(%&("(8D<(*#"<+
§
!9#,(F,59*%;:(O(!9#,(-9-,&;D-
○
Momentum
-
○
!9&2":A(.6(),>;,-8,#( 61.3 _/`6(?!
Document Summary
A body in motion tends to remain in motion. A body at rest tends to remain at rest. Position is described with a vector, direction and distance. First law: an object not subject to outside forces moves at constant velocity, cove equal distances in equal times (inertia) Second law: the force exerted on an object is equal to the product of the object"s mass times its acceleration. The acceleration is the same direction as the force. Easier to move a light object than a heavier one. Example: flicking the pingpong ball vs flicking a baseball. Third law: for every force that one object exerts on a second object, there is an e but oppositely directed force that the second object exerts on the first object. Eg jabbing a pencil into your hand is gonna hurt. Also, the pencil tip is going to break (equal and opposite reaction) Normal force from ground pushes up on barbie.
