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777876981

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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