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If FP> w sin

If the body is about to slide (move) under the effect of its weight

only, then:

The angle of friction = the angle of inclination of the plane in measure

If FP< w sin

FF+ W sin

Fp

R

W sin

FP+ FF

R

=

= ac + bdsuch that: = (a, b) , = (c, d)

= +

Note: = 0 if,= 0 , = 0 or

The algebraic projection of in the direction of =

such that a =

The algebraic projection of in the direction of =

such that b =

The algebraic projection of in the direction of= B cos

The algebraic projection of in the direction of= - B cos

x = x = - x = x = - x = x = -

x = 0 , x = 0 , x = 0

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To find moment:

The moment ofacts at A about B is:MB= x = BA . F . sin or = F . L

1)If line of action passing through the point A, then : MA= 0

2)The algebraic component of force in the direction of =

1) If the force bisects , then: MA= - MB2) If the force is parallel to then: MA= MB

Same Direction:

R = F1+ F2 ( Magnitude)

F1. AB = F2. BC ( Line of action)

A B C

F1F2

R

A B C

F2

F1

R

Opposite Direction:

R = F2F1 ( Magnitude)

F2. AB = F!. AC ( Line of action)

s S 2

s45

45

a c

b

+ =

x

X 3

2 x

30

60

If: F1, F2, and F3are is same way round:

Then,1

=

=

= m

the set of forces is equivalent to a coupleits norm ( Magnitude) = 2 . m . area of triangle

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:Forces)1

1)

2)

2) Planes:

1)

2)

3)

4)

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3) Rod:

1)

2)

33)

4)

5)

6)

7)

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4) Shapes:

1)

2)

3)

4)

5)

) Lamina5

1)

2)

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6) Vectors:

1)

2)

3)

4)

5)

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7) Choose, Complete:

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