Lab Sheet For Mechanics Of Machines

1. -
DJJ30093-Engineering Mechanics
Experiment : Beam Apparatus
: Fundamental of Statics
Topic
Duration : 2 Hours
1.0 Objective
At the end of this experiment student should be able:
a) 'Recognize where forces are acting on a body in two
dimensions
b) Draw a Free-Body-diagram (FBD)
c) Find the resultant force, use the following concepts:
i. -- Sinus's Law
ii. Graphical Methods
2.0 Theory:
The parallelogram of forces is a method for solving (or visualizing)
the results of applying two forces to an object. When more than two
forces are involved, the geometry is no longer parallelogram, but the
same principles apply. Forces, being vectors are observed to obey
the laws of vector addition, and so the overall (resultant) force due to
the application of a number of forces can be found geometrically by
drawing vector arrows for each force. For example, see Figure 1 . This
construction has the same result as moving F2 so its tail coincides
with the head of Fr, and taking the net force as the vector joining the
tail of Fr to the head of Fz. This procedure can be repeated to add Fa
to the resultant F1 + Fz, and so forth.
F,o.=f .+f,
Fr
Prepared by Yuniza Ahmad
Figure 1
2lPage

2. -
DJJ30093-Engineering Mechanics
The law of sinus is useful for computing the lengths of the unknown
sides in a triangle if two angles and one side are known. This is a
common situation occurring in triangulation, a technique to determine
unknown distances by measuring two angles and an accessible
enclosed distance.
Sin a Sin b Sin c
Figure 2
3.0 Apparatus:
B
C
8.
A
C
a)
b)
c)
d)
e)
4.0 Procedure:
Beam Apparatus
5N and 10N weight slot
Strings - 1.3m
Protractor
Meter Rule
a) Assemble the apparatus as shown in Figure 3.
b) Tie a 5N weight slot to middle of a 1.3m string.
c) Use a protractor to measure the angles between the
horizontal axis and string. Record < AC and < BC in Table 1.
d) Using a suitable scale, draw a vector diagram to show the
forces in action (Graphical methods)
e) Repeat all the steps by using 10N weight.
f) Write down your own conclusion from the results of this
experiment.
Prepared by Yuniza Ahmad 3lPage
.;1

3. -
DJJ30093-Engineeri ng Mechanics
5N
r {
String
Weight slot
Beam
apparatus
Figure 3
5.0 Data Collection
Write the outcome of your observation from this experiment.
Table 1
Data of Analysis:
Table 2
Attachment
Graph paper
Calculation using Sinus's Law
i)
ii)
G,6t / g-r
051/ f
5N
G,b/rrf 6'b /10'
10N
l
5N
10N
Prepared by Yuniza Ahmad 4lPage
LOAD

4. -
DJJ30093-Engineering Mechanics
Experiment : Beam Apparatus
Topic : Force in Equilibrium
Duration : 2 Hours
1.0 Objective:
At the end of this experiment student should be able:
a) To illustrate the conceptspf forces and their components
b) Draw a Free-Body-diagram (FBD)
c) Use data taken to prove an equilibrium of force
2.0 Theory:
A particle is said to be in equilibrium if the particle is at rest (if
originally at rest) or has a constant velocity (if originally in motion).
However, the term'equilibriu m' or more precisely'static equilibrium'
is normally used to describe an object at rest. ln order to maintain
equilibrium, it is necessary to satisfy Newton's First Law of Motion.
Newton's First Law of Motion requires that the resultant force acting
on a pafticle to be equal to zero. This condition may be expressed
AS
IF=0.
Where EF is the vector sum of all the forces acting on a pafticle.
And the supporting forces also can be determined via balances of moments.
Balance of moments around support A and B:
IMA=0 RB(L)-FCX=0
RB=FC)(L
FC
RA R3
L
Prepared by Yuniza Ahmad
Figure 1
5lPage

5. -
DJJ30093-Engi neering [Vlechanics
3.0 Apparatus:
4.0 Procedure:
a) Beam Apparatus
b) 10 N weight slot
c) Steel bar
a) Assemble the apparatus as shown in Figure 2.
b) Tie a 10N weight slot to distance X from A.
c) Take a value of force that EUpport using dynamometer
Figure 2
I
Prepared by Yuniza Ahmad SlPage
f
,:
L*ad F
!
{t
p
ax

6. -
DJJ30093-En gi neeri n g [4echanics
Experiment
Topic
Duration
: Simple Pendulum
: Velocity and Acceleration
: 2 Hours
1.0 Objective
At the end of this experiment student should be able:
a) Jo plot a T2- L graph using a simple pendulum.
b) To find the effective length of the simple pendulum for a given time
period using the graph.
c) To calculate the acceleration due to gravity at a place.
2.0 Theory:
An ideal simple pendulum consists of a heavy point mass (called bob) tied
to one end of a per-fectly inextensible, flexible and weightless string. ln
practice, we make it by tying a metallic spherical bob to a fine cotton stitching
thread.
Length of a Simple Pendulum
The distance between the point of suspension of the pendulum and its
Centre of Gravity (C.G.), which is the C.G. of the bob, is called the lengthof
the simple pendulum. lt is represented using the alphabet ( L ).
Time Period of a Simple Pendulum
Time period is the time taken by the bob of the simple pendulum to make
one complete oscillation. lt is represented by the letter T.
Prepared by Yuniza Ahmad Bllrlr

7. -
DJJ30093-Engineering Mechanics
5.0 Data Collection
Write the outcome of your observation from this experiment.
Table 1
Data of Analysis
Table 2
Attachment
i) Calculation
loa ' L"rrt
Ab
6o
-lo
s0
5 6
i,
lo
10 cm
il
ln I
20 cm
3:0-cm
f 2
Z 40 cm aI
4
0.1
0.2
0.3
0.4
Prepared by Yuniza Ahmad TlPage
Data from Experiment Data from Theory
RB (N)

8. -
DJ J 30093- En g i neeri n g lVlecha ni cs
Finding the acceleration due to gravity
The time period of a simple pendulum depends on the length of the
pendulum (l) and the acceleration due to gravity (g), which is expressed by
the relation,
L
T*3
For small amplitude of oscillations,
__t
l r : rln'-
':*=[#J
,tt]
u
L
i]1 .
ie; u*4ml
t-
lf we know the value of L and T, we can calculate the acceleration due to
gravity, g.
The T2 against L graph
We can plot a graph between T2 and L by taking T2 along the Y axis and L
along the X axis. The graph is a straight line.
t"
From the graph,
L AE.
I **
i
I
FJ
Prepared by Yuniza Ahmad 9lPage
1:

9. -
DJJ30093-Engineering Mechanics
3.0 Apparatus
4.0 Procedure
a) Piece of string
b) Pendulum bob
c) Pair of small flat pieces of wood or cork
d) Reton stand with a clamp
e) Stop watch
0 Meter rule
g) Protractor
h) Opticalpin
i) Pair of scissors
a) S&-up a simple pendulum as in Figure 1
Figure 1
b) Measure the length, / of the pendulum
c) Swing the pendulum at less than 10o from the vertical in one plane
and measure the time for 10 oscillations. Repeat the operation and
calculate the average value. Then, determine the period of
oscillation, Iof the pendulum.
d) Repeat step (c) at least 3 times with different values of length, / of
the pendulum. Record the values for / and f in Table 1.
-r*r
r/i:
It Lt .li
't*iifi
,$,1*p wsteln
Prepared by Yuniza Ahmad l0 llage
Splil r*rk
*{10*
A
E*t:

10. -
DJJ30093-Engineering Mechanics
5.0 Data Gollection
Data of Analysis
Attachment
i) Graph paper
ii) Calculation
Table 1
,r,,q tq ,1u t-Gu
50
60
t6.sl la"q 16 .)o
lL.q, t6 ,€o l(,,+e
ll .f6 ll.+n
80
n ,66
t&.73 tk-7e
90
ts.g3
Prepared by Yuniza Ahmad 11 lPage
10
.lll.l.llllll,l:liltdSglh,l:,l,,..':tiillt:
l,i iii ilil.i:ii:uutu,lltlttttQl lill,l:}',1:t:,,.;
iil.:i)tlt:-i::iiiil:rrtltr::,rt:::airtliiiiriilllllrlit]1ii:iiilliiiriiia,::ir
Ddta,,,_f iQm,,,Era,p.h.,..
Gravity, g
(m/s2)
0.5
0.6
0.7
0.8
0.9

11. .-
DJJ30093-Engi neering Mechanics
Experiment
Topic
Duration
: lncline Plane
: Force and Motion
: 2 Hours
1.0 Objective:
At the end of this experiment student should be able
To determine the coefficients of:
a) static friction
b) kinetic friction
2.0 Theory:
Static friction
mq
Figure 1
Referring to Figure '1
, if force, P is increased; frictional force, F, also increase
accordingly and the object will remain at rest. However, for a certain value of
P, the object stafts to move. At this stage, the frictional force is known asthe
limiting static frictional force, fs which are the maximum value of P.
Kinetic friction
lf the object is in motion, the frictional force is known as kinetic friction, fi..
The kinetic frictional force is less than the static frictional force. That explains
why it is difficult to move an object which is initially at rest, but once it is in
motion, less force is needed to maintain the motion.
I : p.'o
Prepared by Yuniza Ahmad
rt F,K R
12 lPage
Fr
r

12. -
DJJ30093-Engineering Mechanics
Material Types and Coefficients
3.0 Apparatus
a) lnclined plane
b) A steel block
c) Slotted mass with hooks
d) String
4.0 Procedure
a) Set up the apparatus as in Figure 2. Make sure that the string from
the block is tied up horizontally to the pulley.
Copper u = 0.20
Aluminium p =0.25
u =0.15
Steel
u =0.30
Plastic (Polypropylene)
Prepared by Yuniza Ahmad
Figure 2
13 lPage

13. DJJ30093-Engineering lVlechanics
b) Add the slotted weight onto the hook gradually until the block
begins to slip. Record the total weight, [4/rin table 1. Repeat 3
times to get the average value of Wl
c) Add different weight, Wo onto the block and repeat step (b).
d) Repeat step (c) for at least 3 different values of Wu.
e) Repeat step (b) but exert a little push to the block every time each
mass added. Record the mass, 1,4/rin table 2 when the block moves
slowly and steadily along the inclined plane.
0 Add different weight, Wa onto the block and repeat step (e)
S) Repeat step (f) for at least 3 different values of Wo.
5.0 Data Collection
Block of steel weight, Wu = 10 N
Table 1: Total weight for Static Friction
Table 2: Total weight for Kinetic Friction
k5
0
.5 4,5
t, tr-
b'J e"s 65
5
1.5 15
10
1.5
Prepared by Yuniza Ahmad 14 lP:;r
wd (N)
Wr (N)
2 3 Average
Average
1
0
5
10

14. -
DJJ30093-Engineering Mechanics
a) Plot a graph of f"against R where fs= Wrand R = Wa+ Wn.
Determine p", the coefficient of static friction from the graph
b) Plot a graph of fLagainst R where fs= Wrand R = Wa+ Wo.
Determine fl,, the coefficient of static friction from the graph
Data of Analysis
Attachment
i. Graph paper
ii. Calculation
'10
15
20
Prepared by Yuniza Ahmad 15 lFage
Static friction, ps Kinetic friction, ;.tr
,,Daielfiom,l
t...::::t t' : .gf eih.,,: :,:,,,.
Data from
graph