Structures & MaterialsHigher Technological Studies Technological Studies Structures & Materials Required Knowledge

Structures & MaterialsHigher Technological Studies

Technological Studies

Structures & Materials

Required Knowledge


Learning Outcome 1

•Reactions at supports .

•Moments about a beam; and

•Resolution of Forces;


The HAND!

Vertical Forces

Moments

Pythagoras Horizontal Forces

Trigonometry

Remember & Apply the following in order


Three conditions that will ALWAYS be true:

ΣM = 0

ΣFv = 0

ΣFh = 0

Equilibrium

The sum of all Moments = 0

The sum of all Vertical Forces = 0

The sum of all Horizontal Forces = 0


Three conditions that will ALWAYS be true:

ΣM = 0

ΣFv = 0

ΣFh = 0

Equilibrium

The sum of all Moments = 0

The sum of all Vertical Forces = 0

The sum of all Horizontal Forces = 0


MomentsA MOMENT is a force -

that causes a turning motion.

Moment = Force x Distance


MomentsA MOMENT is a force -

that causes a turning motion.

Moment = Force x Distance

FL1 FL2

FR


ForcesA Forces has:

20NMAGNATUDE

DIRECTION20N

Positive Forces are:

Negative Forces are:


ForcesPut together:

Positive Forces are:

Negative Forces are:


Vertical ForcesΣFv =

0The sum of all Vertical Forces = 0

Positive Forces

Negative Forces

20N 20N

40N

40N

20N

+ 40N

- 20N


Horizontal ForcesΣFh = 0

The sum of all Horizontal Forces = 0 20N

20N

40N

Positive Forces

Negative Forces

20N

40N

+ 20N

- 40N


PythagorasPythagoras’ Theorem: For a right angle

triangle;The square of the length of the hypotenuse is equal to the sum of the squares of the lengths of the other two sides.

c2 = a2 +b2

c =(a2 +b2)

c

a

b


PythagorasPythagoras’ Theorem:

c2 = a2 +b2

ca

b

C

A

B


Trigonometry

30o

AC

B

b

c

a

SOH CAH TOA For right angle triangles only

sin A = Opposite (a)Hypotenuse

(c)

cos A = Adjacent (b)Hypotenuse (c)

tan A = Opposite (a)Adjacent (b)


SupportsThere are 3 types that will be used in this module

Knife-edge:This is a fixed support that only provides a vertical reaction

Roller:

This support is not fixed and can only provides a vertical reaction

Hinge:

This support is fixed but will allow movement and provides a reaction in any direction


Answer & units

Problem Solving TechniqueThe RECIPE (for any calculation):

State formulaThis will focus your thoughts and often get you marks

TransposeRe-arrange formula to suite need

Substitute Insert the numbers

Calculate Do the Maths

Lose marks if no units


Problem Solving TechniqueExample:

To find the horizontal force (FH)

State formula

= cos A x Hyp.

FHTranspose

cos A = Adjacent (b)Hypotenuse (c)

FHHyp.

=

Substitute = cos 30o x 90N

FH

CalculateAnswer & units

= 77.94N

FH

30o

90N

FH

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Structures & MaterialsHigher Technological Studies Technological Studies Structures & Materials Required Knowledge