3)Lab Report Engineering Mechanics 2 (Flywheel )

PRECAUTIONS :

1. Do not stand too close to the tile when releasing the mass. 2. The turns of the string must not overlap the other. 3. Stop Watch must be handled with care in order to avoid any error in the reading. 4. The first few turns of the string should overlap the others. 5. The mass should be wound up to the same height in all trials.

Apparatus 1 2 3 4 5 6 7 8

Bench-top A vertical board with one pulleys with ball bearings Rope one weight hangers Weights set Load hanger Stainless steel Ruler Pencil

Procedure

1. The flywheel is set with the axle of the flywheel horizontal. 2. The vernier caliper is used to measure the diameter d of the axle. The mean of two perpendicular measurements was taken. 3. The hanger with appropriate amount of slotted mass is put on the tile. Which is used the balance to measure the total mass m. 4. The mass is winded to an appropriate height. Verified that the string fell off the axle when the mass hit the ground. 5. The height h of the mass is measured. The height h was recorded. 6. The mass is released then and at the same time the stop-watch is started. 7. As soon as the mass hit the ground, timing was stopped and the number of revolution the wheel revolved is taken. 8. The mass is winded up again and steps are repeated for at least 3 times.The mean time of the falling is obtained.

Data Result

Flywheel Experiment Data Variable s 1 2 3 4 5

Load(g ) 700g 900g 1100g 1300g 1500g

Flywheel Without Load Time (s)

Variables

Load(g ) 700g 900g 1100g 1300g 1500g

Flywheel With Load Time(s)

1 2 3 4 5

13.59s 9.90s 8.59s 7.59s 6.75s

Flywheel Theoretical Data

Analysis and disscussion

0s 14.93s 10.38s 9.16s 8.16s

Moment of Inertia (I) 316.78 215.97 198.62 183.14 167.02

Force (KN)

Moment of Inertia (I) -0.28 491.65 290.23 266.10 244.35

Force (N)

6.9 8.8 10.8 12.8 14.7

6.9 8.8 10.8 12.8 14.7

Graph Force Versus Displacement (Theoretical)

Graph Force Versus Displacement (Experimental)

Disscussion Applications Common uses of a flywheel include:

Foot operated sewing machine.

It consist of two wheel , one big and one small . The wheel are connected by rope . when a motion is given at bigger wheel , the rope transfer this motion to the smaller wheel , This smaller wheel act as a pulley and runs the sewing machine.Even when we stop suppling driving force to the bigger wheel , it still continue for a short time because of the moment of inertia it posesses . Flywheel is a device that act as energy resevoir , storing and supplying mechanical energy when required.

Ship stabilizing gyroscopes

This are a technology developed in the 19th century and early 20th century and used to stabilize roll motions in ocean-going ships. It lost favor in this application to hydrodynamic roll stabilizer fins because of reduced cost and weight. However, more recently (since the 1990s) a growing interest in the device has reemerged for low speed roll stabilization of vessels. The gyroscope does not rely on the forward speed of the ship to generate a roll stabilizing moment and therefore has shown to be attractive to motor yacht owners for use whilst at an anchorage.One of the most famous ships to first use an anti-rolling gyro was the 1930 Italian passenger liner the SS Conte di Savoia which had three huge gyros to control roll.The ship gyroscopic stabilizer typically operates by constraining the gyroscope's roll axis and allowing it to "precess" either in the pitch or the yaw axes. Allowing it to precess as the ship rolls causes its spinning rotor to generate a counteracting roll stabilizing moment to that generated by the waves on the ship's hull. Its ability to effectively do this is dependent on a range of factors that include its size, weight and angular momentum. It is also affected by the roll period of the ship. Effective ship installations require approximately 3% to 5% of a vessel's displacement.Unlike hydrodynamic roll stabilizing fins, the ship gyroscopic stabilizer can only produce a limited roll stabilizing moment that may be exceeded as the wave height increases. Otherwise, it is not unusual for the manufacturer to recommend that the unit not be used at sea in large waves.

Possible cause of error (other than paralax error)

This experiment there are some things that need to be discussed among which are the source of the error and use in industry. Among the sources of error in this experiment there are friction at the pulleys, that error can be ignored because of no calculation are related about friction. In addition, size of both pulleys also can be ignored because no specific details about the size and types of pulleys that has been used. Vibration also are types of error can be discussed because, vibration exist during the experiment running, its came from factor of surrounding. Futhermore, reading error also can be classified as source of error, when the results came out, the people who took the result should be alert and aware about how to do calculation and the data they need to complete the graph. The error on the hanger load can also be ignored because the purpose of the experiment to analyze the difference distance from the initial point to the end point , this experiment also to studying how much mass needed to attract mass remains found on the hanger load.

CONCLUSION In conclusion, moment of inertia of the flywheel is approximately consistent with small deviations in short range for both experimental and theoretical results. Part 1; experimental I= 0.136 kg.m2 theoretical I=0.150 kg.m2 2 Part 2; experimental I=0.101 kg.m theoretical I=0.106 kg.m2 Part 3; experimental I=0.0821 kg.m2 theoretical I=0.0903 kg.m2 Part 4; experimental I=0.148 kg.m2 theoretical I=0.134 kg.m2 Since the percentage of discrepancy of each part from 1 to 4, 9.33%, 4.72%, 9.08% and 10.45% respectively, all are less than 15%, experimental values of moment of inertia of flywheel are considered accurate and reliable.

As it can be seen above that the values for the time and the range of the time are greater forthe experimental values’graph than the calculated values’graph, this can be due to the reasonsof ignoring the

friction between the axle and the slope theoretically and also ignoring the mass of the axle which in turn led to the polar moment of inertia also being less, the air resistance that increases with speed is also not considered, there is always human error when measuring the time of a moving system as with the increase of the distance moved the wheel gains somuch speed that the stopwatch can either be stopped just before the wheel and axle reachesthe end point or after it passes the end point. All these are the reasons why the actual valuesfor time were almost half of the calculated values, hence the percentage error of the values of time is almost 50%, while for velocity it was almost 30% and for acceleration almost 52% asall these resistive factors were neglected during calculation. It can also be seen that theacceleration values are constant for the calculated values and for the actual values it isincreases until it is constant. This is due to inertia of the system.

REFERENCES 1 D. Halliday, R. Resnick, and J. walker. Fundamentals of physics. 6th edition. Wiley, 2003. 2

Ferd Beer and Russ Johnston (2005)Vector Mechanics For Engineers: Statics, New Jersey, McGraw-Hill

3

Gabrys CW. High performance composite flywheel, US patent pub. NO : US 2001/0054856 A1; 27 Dec 2001. En.wikipedia.org/wiki/flywheel

4 5 6 7 8 9

.Wheel and Axle, The World Book Encyclopedia, World Book Inc., 1998, pp. 280-281Elroy McKendree Avery, Elementary Physics, New YorkSheldon & Company, 1878.2. Bowser, Edward Albert. An elementary treatise on analytic mechanics: with numerousexamples. (Originally from the University of Michigan) D. Van Nostrand Company, 1890 pp. 1903. Fuller RW and Brownlee RB, Laboratory Exercises to Accompany Carhart and Chute’s First Principles of Physics. swagn and Bacon, 1913 pp. 107-1094. Bowser, Edward Albert. An elementary treatise on analytic mechanics: with numerousexamples. (Originally from the University of Michigan) D. Van Nostrand Company, 1890 pp. 190and following5. Baker, C.E. The Principles and Practice of Statics and Dynamics … for the Use of Schools and Private Students. London: John Weale, 59, High Holborn. 1851 pp. 26-29