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h i r o s h m e n d i s @ g m a i l . c o m
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Copyright © Science Academy
Boralesgamuwa
All right reserved
First print 2016
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General certificate of ordinary level examination
Science
Grade 10
Units 9, 11, & 12
Resultant force
Equil ibrium of Forces
Turning effect of a force
Hirosh Mendis
Science Academy 0 7 7 7 8 7 6 9 8 1
h i r o s h m e n d i s @ g m a i l . c o m
Contents Resultant force .........................................................................................5
The resultant force of two collinear forces .........................................6
Resultant of collinear forces acting along the same direction ........6
Resultant of two collinear forces acting along opposite direction ..6
Resultant of two parallel forces ...........................................................7
Resultant of two non – parallel forces .................................................7
Equilibrium of Forces ............................................................................ 12
Equilibrium of a body under two forces ........................................... 12
Equilibrium of a body under three coplanar parallel forces ............. 13
Equilibrium of a body under three forces that are not parallel ....... 14
Turning effect of a force ....................................................................... 16
Moment of a force ............................................................................ 16
Investigation of the dependence of the moment on the magnitude
of the force. .................................................................................. 16
Investigation of the dependence of the moment on the
perpendicular distance to the force from the point of suspension
...................................................................................................... 18
Direction of the moment of force and equilibrium of object under
the action of the moments of force .............................................. 19
The principle of moments ............................................................. 20
Examples of moment .................................................................... 20
The couple of forces ......................................................................... 27
Moment of a couple of force ........................................................ 27
Applications of couple of forces ................................................... 28
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
5
o
o
o
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
6
The resultant force of two collinear forces
Resultant of collinear forces acting along the same direction
Resultant of two collinear forces acting along opposite direction
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
7
Resultant of two parallel forces
Resultant of two non – parallel forces
3 N
4 N
3 N
4 N
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
8
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
9
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
10
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
11
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
12
Equilibrium of a body under two forces
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
13
Equilibrium of a body under three coplanar parallel forces
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
14
Equilibrium of a body under three forces that are not parallel
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
15
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
16
Moment of a force
Investigation of the dependence of the moment on the magnitude of the force.
Table Rubber washers & screw Meter rule
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
17
Newton balance
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
18
Investigation of the dependence of the moment on the perpendicular distance to the force from the point of suspension
¼
¼
Newton balance Loop of thread
Table Rubber washers & screw Meter rule
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
19
Direction of the moment of force and equilibrium of object under the action of the moments of force
F1 F2
d1 d2
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
20
The principle of moments
Examples of moment
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
21
5 N 10 N
40 cm x
2 kg 40 cm 30 cm
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
22
1 m 2 m 4 m
25 N 30 N F
5 m
2 m x 10 N
30 N 20 N
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
23
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
24
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
25
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
26
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
27
The couple of forces
Moment of a couple of force
U n i t s 9 , 1 1 & 12 R e s u l t a n t F o rc e E q u i l i b r i u m a n d M o m e n t
Hirosh Mendis (B. Sc.) For a different future
28
Applications of couple of forces
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