7/25/2019 Mechanics of Solids Assignment 1

1/4

A60

RAy

RB600N

2m2m

VA

1.5kN

Wsin

Wcos2.5kN

1m1m

5m1.1

NR

NR

Ay

AH

525

130

=

=

If the lae! is "lace a#ainst a smooth s$!face%then RA&' 0( the ho!i)ontal com"onent of RB*ill not +e

+alance an the lae! *ill sta!t mo,in#.

1.3

(a) kNW 5.6=

kNmMA 2-.=

(b) AM has a ma/im$m ma#nit$e of 2.5kNm

A

AAZ

MW

MWM

=

=+=13sin3

05.225.13sin0

AM can +e ,e W3 o! 4,e W3

Acco!in#ly% sin3

13 AMW

=

kNW

kNW

-6.1

-3.

ma/

min

=

=

RA&

7/25/2019 Mechanics of Solids Assignment 1

2/4

Ay

ByB7A7

7

-0-0

)

y/

1.4

( )

( )

0813500

3

1828828

5.1

185.085.085.18

888

=++=

+==

++==

++=

jFFRF

kjiFFF

kjiFFF

NkRjRiRR

BGEFA

BGBGBGBG

EFEFEFEF

zyxA

03

2

5.1

5.08

013503

1

5.1

5.08

03

2

5.1

5.18

=+

=+

=

BGEFz

BGEFy

BGEFx

FFRk

FFRj

FFRi

08135088285.1

90

=+

=jiFiFi

M

BGEF

A

:se e/"!essions of EFF an BGF

f!om ;A< an then collect coefficients of j8

an k8

9

NF

NF

FFk

FFj

EF

BG

BGBG

BGEF

150

505

1350

3

2

5.1

5.05.111.38

11.38

=

=

=+

=

!om ;B

7/25/2019 Mechanics of Solids Assignment 1

3/4

@$ation of moto!9

NFFM

FFMNFFM

FFFF

FFF

satisfiedyidenticallF

BYBYAX

CZBZAX

CZCZAX

CZBZAZY

BYAYY

X

500160-010090

0-020102011016090

205200150105011010010090

090

010090

0

==+=

=++===++=

=++=

==

=

!om othe! e@$ations%

NkjFNkjF

NFNFNF

BA

AZAYBZ

85.3185085.22850

5.22505.31

+==

===

1.6 Ass$me a #ene!al f!iction coefficient f.

When the *e#e is mo,in#% tan#ential fo!ce at contact ' f / no!mal fo!ce

(a3 !a* B of AB an of *e#e. onsie! e@$ili+!i$m of AB an of *e#e9

Col$tion leas to9

++=

f

ff

5.0-66.0

5.0-66.05

o! kNf -2.63.0 ==

(b3 If f is ,e!y small% the *e#e *ill sli" o$t *hen the fo!ce D is !emo,e. Ehe +o!e!line occ$!s

*hen the *e#e is F$st "!e,ente f!om sli""in# o$t +y the f!iction fo!ces. We #o th!o$#h the

"!e,io$s analysis% !e"lacin# f+y 4fe,e!y*he!e% +eca$se the tenency *e a!e in,esti#atin# no*

is the sli""in# in the o""osite i!ection.

Eh$s9

( )!"#de#lineffff

ei

f

ff

2.005.0-66.0

5.0-66.0

0..

5.0-66.0

5.0-66.05

==+

+

=

+

++=

1.

7/25/2019 Mechanics of Solids Assignment 1

4/4