chnical universityTafila te

Facultry of engineering

Title: lab report of mechanical equivalent.

Student name: salam albaradie.

Date of submission: 19/11/2013

Lecturer name : dr.ali alahmer.

Introduction

The original development of the law of conservation of energy proceeded slowly. One of the last important ideas that was needed for a complete, consistent theory was the development of the science of thermodynamics. Finding the connection between mechanical energy and heat (thermal energy) was a crucial step in this understanding. Joule did the original experiment to find an equivalence between the units of mechanical energy (in Joules!) and units of heat (calories). His experiment dealt with a system of falling weights that converted the lost potential energy of the system into thermal energy in a container of water that was being stirred by a paddle driven by the falling

weights. Our experiment is similar in nature. We will do work on our system by turning a handle against the force of friction and using this energy to warm an aluminum cylinder. Thus the mechanical energy introduced into our system will be the work done by friction. The work (in Joules) done by a friction force can be calculated by

1) Wf = f ∆s = f (2 π r) N, where f is the friction force, r is the radius of the cylinder and N is the number of turns

through which the cylinder rotates. The heat energy, ∆Q, (in calories) transferred into the aluminum cylinder can be Calculated by observing the temperature, ∆T, rise of the aluminum and calculating the following:

2) ∆Q = m C ∆T

Theory

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Methodology

Data Analysis

J(j/cal) Q (cal) W (j) Temp © N of rev

0 0 0 20 0 o

2.11 1.4961 8.3163 24 200 1

2.12 8833621 214862 28 400 2

1.95 ....63. 1.29.68. 33 600 3

1.87 2.28693 1982261. 38 800 4

1.922 48126.4 124.3649 42 1000 5

0

5

10

15

20

25

30

35

40

45

0 200 400 600 800 1000 1200

Tem

p

N of rev

Sample of Calculation

( )

)

) ))

)

Conclusion

From the above analysis we can see that the liner relation between temp and Number of

cannot be heat But all amount of work can be converted to equivalent heat. Allrevolution

the accurate value foe j is 4.18 j/cal if you take the average of converted to work

the percent of error is 52.2%