Upload
lseah850123
View
241
Download
0
Embed Size (px)
Citation preview
7/25/2019 Chapter 10 (Done)
1/9
CHAPTER 10
SIMPLEMACHINE
1
7/25/2019 Chapter 10 (Done)
2/9
10.1 Levers
Lever
- is a simple machine
- enables a small efort to overcomea heavy load
- can be used to lit heavy objects
- makes work easier
2
7/25/2019 Chapter 10 (Done)
3/9
A lever has three parts
- ulcrum !"# $ the turnin% point or pivot- efort ! $ the orce applied toovercome a resistin% orce called the load
- load !L# $ the resistin% orce e'erted byan object
Lever can be classi(ed into
- (rst class
- second class
- third class
)
7/25/2019 Chapter 10 (Done)
4/9
"irst class lever
"ulcrum is between the efort and theload
*mall efort is used to move a lar%eload
&fort is urther rom the ulcrumthan the load
&fort moves throu%h a lon%erdistance than the load
+
7/25/2019 Chapter 10 (Done)
5/9
*econd class lever
,he load is between the ulcrum andthe efort
*mall efort is used to move a lar%eload
&fort is urther rom the ulcrumthan the load is
&fort moves throu%h a lon%erdistance than the load
7/25/2019 Chapter 10 (Done)
6/9
,hird class lever
,he efort is between the ulcrumand the load
A lar%e efort is used to move a smallload
Load is urther rom the ulcrum thanthe efort is
,he load moves throu%h a lon%erdistance than the efort
7/25/2019 Chapter 10 (Done)
7/9
/hen we loosen a bolt usin% aspanner a orce that is applied has a
turnin% efect on the spanner ,his turnin% efect o a orce is known
as the moment o a orce
,he turnin% efect or moment o aorce is inuenced by
- the ma%nitude o the orce applied
- the position o the orce applied ,he *. unit or measurin% the
moment o a orce is newton-
metre!3m# 4
7/25/2019 Chapter 10 (Done)
8/9
,he moment o a orce can be
calculated by usin% the ormulabelow
moment o a orce 5
orce ' perpendicular distance rom the pivot to theorce
,he principle o moment can be represented bythe ollowin% ormula
load ' 5 efort '
distance o load romthe ulcrum
distance o efort romthe ulcrum
6
7/25/2019 Chapter 10 (Done)
9/9
10.2 appreciatin% the innovative efort in
the desi%n o machines to simpliy work
7uman bein%s make use o the principleo lever to invent machines.
nnovative eforts in inventin% machines
make our work easier. 8omple' machines help us to carry out
di9cult and tedious work.
&'ample o some machines that can arebased on the principle o levers are cranetypewriter pedal bin and paper cutter.
: