machine discussion + result.docx

8/10/2019 machine discussion + result.docx

1/8

1. Muhammad Nur Ikhwan bin Mazli 168699

2. Vincent Ong Shu Lin 168798

3. Yokasundery A/P Muniandy 168636

Lecturer :Dr.Mohd Roshdi bin Hassan

Date conduct experiment : 30th

October 2014

Date of Submission : 6th

November 2014

Department of Mechanical and Manufacturing

Engineering

EMM 3504 Machine Mechanics

Laboratory Report:DETERMINATION OF MOMENTUM OF INERTIA

OF A GYROSCOPE DISK

Semester : Semester 1, 2014/2015

Group : B4

Group Members:
http://profile.upm.edu.my/barkawi/en/profail.htmlhttp://profile.upm.edu.my/barkawi/en/profail.html


2/8

EXPERIMENT:

Result

Also obtained,

Solid cylinder (disc) = 900g

Hollow = 900g

Drive weight = 100g

Experimental, r = 0.01m

= 11cm

= 12cm

= 12cmPart 1: Distance, h = 69cm

Types Time (s)

1 2 3 Average

Solid 2.84 2.02 2.16 2.34

Hollow 3.04 2.87 3.13 3.103

Table 1: Result for experiment part 1.

Referring to the values in table above obtained during the experiment used to calculate inertia,

I:

Equations for calculating the moment of inertia for both theoretically and experimentally are

as follows:

Theoretically

(A) Solid cylinder

= m = (1/8) x 0.9kg x ( = 1.62 x


3/8

(B) Hollow

= m ( )

= (1/8) x 0.9kg x ( ) = 2.98 x Experimentally

I=

= ()(( (= 3.97 x kg

= ()(( (= 6.58 x

Types Theoretical value Experimental value Percentage error (%)

Solid 1.62 x 3.97 x kg 75.5Hollow 2.98 x 6.58 x 77.9

Table 2: Percentage of error for hollow and solid.


4/8

Part 2:

Distance, = 26cmHeight of hanging load, h: 69 cm

Distance, d1: 260 mm

Mass of load: 100g

Mass (g) Time (s)

1 2 3 Average

200 7.60 7.30 7.49 7.463

400 10.33 10.57 10.17 10.357

800 13.92 13.97 13.92 13.937

Table 3: Time readings for different mass of loads at 260 mm.

Distance, = 6cmHeight of hanging load, h: 69 cm

Distance, d2: 60 mm

Mass of load: 100g

Mass (g) Time (s)

1 2 3 Average

200 3.51 3.50 3.57 3.527

400 3.87 4.00 3.91 3.927

800 4.82 4.69 4.78 4.763

Table 4: Time readings for different mass of loads at 60 mm.


5/8

Sample calculation for theoretical moment of inertia:

((= Sample of calculation for experimental value moment of inertia:

()(

( (=

Theoretical value for moment

of inertia,(x10-4kg m2)Experimental value for

moment of inertia,100 g D = 60 mm 3.6 9.01

D = 260mm 67.6 40.4

200 g D = 60 mm 7.2 11.2

D = 260mm 135.2 77.7

400 g D = 60 mm 14.4 16.4

D = 260mm 270.4 140.8

Table 5: Values for theoretical and experimental for different mass.


6/8

Figure 1: Graph of Ix vs Mass for D = 60mm

Figure 2: Graph of Ix vs Mass for D = 260mm.

0

2

4

6

8

10

1214

16

18

0 100 200 300 400 500

InertiaMoment((x10-4k

gm2)

Mass (g)

Graph of Ix vs Mass for D = 60mm

Theoretical Ix value

Experimental Ix value

0

50

100

150

200

250

300

0 100 200 300 400 500

InertiaMoment((x10-4kg

m2)

Mass (g)

Graph of Ix vs Mass for D = 260mm

Theoretical Ix value

Experimental Ix value


7/8

Discussion

From the experiment part 1 above, we found out that hollow cylinder took longer time in

order to let the drive weight to reach the bottom compared with solid cylinder. This is

because hollow cylinder has a higher moment of inertia compared to solid cylinder. Hence,

hollow cylinder has a lower angular acceleration due to its high moment of inertia compared

to the solid cylinder.

Meanwhile, for the experiment part 2, we found out that when the distance between 2

masses longer, time taken to let the drive weight to reach the bottom point longer. This is

because the longer the distance between the masses, the higher the inertia of moment, hence,

the lower the angular acceleration. So more time needed in order to let the drive weight

reaches the bottom point.

Besides, we also found out that the heavier the mass, time taken to let the drive weight

to reach the bottom point longer. This is because the heavier the mass, the higher the inertia

of moment, hence, the lower the angular acceleration. So more time needed in order to let the

drive weight reaches the bottom point.

There is some percentage error in the experiment. This is due to some errors such as

human error and random error. For human error, there is some delay when we take the time

taken as the drive weight reached the bottom point. This is because one of the member need

to observe whether the drive weight have reach the bottom point or not and another member

handled the stopwatch. Hence, there is some delay when both members communicate with

each other in order to record the time taken as the drive weight reached the bottom point. The

random error is affected by the environment where the experiment carried out. For an

example, there is some air movement in the laboratory which produced by the air conditioner,

hence, this will affect the quality of the result. So in order to improve the accuracy of the

result, the experiment should carried out at a place without air movement.

Industrial application

Flywheels are often used to provide continuous energy in systems where the energy

source is not continuous. In such cases, the flywheel stores energy when torque is applied by

the energy source, and it releases stored energy when the energy source is not applying torque

to it. For example, a flywheel is used to maintain constant angular velocity ofthecrankshaft in a reciprocating engine. In this case, the flywheel which is mounted on the
http://en.wikipedia.org/wiki/Crankshafthttp://en.wikipedia.org/wiki/Crankshaft


8/8

crankshaft stores energy when torque is exerted on it by a firingpiston,and it releases energy

to its mechanical loads when no piston is exerting torque on it. Other examples of this

arefriction motors,which use flywheel energy to power devices such astoy cars.

A flywheel may also be used to supply intermittent pulses of energy at transfer rates

that exceed the abilities of its energy source, or when such pulses would disrupt the energy

supply (e.g., public electric network). This is achieved by accumulating stored energy in the

flywheel over a period of time, at a rate that is compatible with the energy source, and then

releasing that energy at a much higher rate over a relatively short time. For example,

flywheels are used inriveting machines to store energy from the motor and release it during

the riveting operation.

The phenomenon ofprecession has to be considered when using flywheels in

vehicles. A rotating flywheel responds to any momentum that tends to change the direction of

its axis of rotation by a resulting precession rotation. A vehicle with a vertical-axis flywheel

would experience a lateral momentum when passing the top of a hill or the bottom of a valley

(roll momentum in response to a pitch change). Two counter-rotating flywheels may be

needed to eliminate this effect. This effect is leveraged in reaction wheels,a type of flywheel

employed in satellites in which the flywheel is used to orient the satellite's instruments

without thruster rockets.

Conclusion

This report has discussed the momentum of inertia of a gyroscope disk by

measurement of its angular acceleration. Where the hollow cylinder took longer time in order

to let the drive weight to reach the bottom compared with solid cylinder due to its inertia. The

objectives of this experiment was achieved. But due to some errors, the value that we get may

slightly different from the theoretical value.
http://en.wikipedia.org/wiki/Pistonhttp://en.wikipedia.org/wiki/Friction_motorhttp://en.wikipedia.org/wiki/Toy_carhttp://en.wikipedia.org/wiki/Riveting_machineshttp://en.wikipedia.org/wiki/Precessionhttp://en.wiktionary.org/wiki/rollhttp://en.wikipedia.org/wiki/Reaction_wheelhttp://en.wikipedia.org/wiki/Reaction_wheelhttp://en.wiktionary.org/wiki/rollhttp://en.wikipedia.org/wiki/Precessionhttp://en.wikipedia.org/wiki/Riveting_machineshttp://en.wikipedia.org/wiki/Toy_carhttp://en.wikipedia.org/wiki/Friction_motorhttp://en.wikipedia.org/wiki/Piston

machine discussion + result.docx

Documents

Transcript of machine discussion + result.docx