CHAPTER ONE
1.0 INTRODUCTION
1.1 BACKGROUND OF STUDY
Gravity is one of the most extensively studied phenomena in nature. At the macroscopic level, the observation of the interplay of the gravitational force and finite mass systems is commonplace. The trajectory of a falling object, orbits of celestial bodies, and motion of a pendulum all exhibit explicit dependencies on gravity. In lay terminology, gravity is generally described as a force by which systems with mass attract one another. However, as elucidated by Einstein in his seminal works on general relativity, it is now known that gravity’s influence extends to massless systems, such as light, and even space itself (Albert Einstein, 1909). Needless to say, a proper understanding of this ever-present phenomenon is vital for the development of a complete description of the observable universe and nature itself.
The first documented effort towards a quantitative description of gravity was the product of Sir Isaac Newton and Robert Hooke in 1666. Newton, spurred on by the suggestion of Hooke that gravity was an attractive force whose magnitude depended on the inverse square of the distance between interacting systems, began by investigating planetary motion. Through observations of bodies in the solar system, Newton developed and empirically confirmed a number of mathematical relations that ultimately served to validate the previously a-priori inverse square law
One of the first experimental ventures into measuring the gravitational constant was performed by Henry Cavendish in 1798. Following after the work of geologist John Michell and Francis John Hyde Wollaston, Cavendish developed an apparatus to measure the nearly imperceptible gravitational attraction between a pair of small and large lead spheres. Cavendish’s device consisted of a torsion balance – a wooden rod suspended by a thin wire – with two small lead spheres at the ends. A significantly larger spherical lead mass was then positioned near each small sphere. The attraction between each large and corresponding small sphere caused the balance to rotate, thereby precipitating the twisting of the thin wire. After twisting through a particular angle, the torque induced on the balance by the gravitational attraction was balanced by the oppositely-directed torsion torque. Measurement of this angle, along with the imparted torque, allowed for the calculation of G.
1.2 STATEMENT OF THE PROBLEM
Gravity is one of the most important aspects of physics; gravity plays a significant role in our daily lives. However there is a variation in the measurement of Newton’s universal gravitation G; this could be as a difference in location where the experiments are being conducted. It is to this regard that the researcher desired to carry out a comparative analysis on the measurement gravitational constant G using different methods
1.3 AIM AND OBJECTIVES OF THE STUDY
The main aim of the research work is to compare various method used in measuring the gravitational constant G. Other specific objectives of the study are:
1. to measure the gravitational constant G using simple pendulum
2. to measure the gravitational constant G using beam balance
3. to investigate on the factors affecting the measurement of the gravitational constant G
4. to determine the difference in measurement of the gravitational constant G using simple pendulum and beam balance
1.4 RESEARCH QUESTIONS
The study came up with research questions so as to ascertain the above stated objectives of the study. The research questions for the study are:
1. to measure the gravitational constant G using simple pendulum
2. to measure the gravitational constant G using beam balance
3. to investigate on the factors affecting the measurement of the gravitational constant G
4. to determine the difference in measurement of the gravitational constant G using simple pendulum and beam balance
1.5 SIGNIFICANCE OF STUDY
The study on various method used in measuring the gravitational constant G will be of immense benefit to the entire physics departments in the tertiary institutions in Nigeria in the following ways:
1. to will educate the physics students and lecturers on the various method used in the determination of gravitational constant G using beam balance and simple pendulum method
2. it will compare the both methods to determine the level of accuracy in comparism with the gravitational constant G
3. the study will contribute to the body of the existing literature on Newton’s law of universal gravitation
1.6 SCOPE OF THE STUDY
The study on various method used in measuring the gravitational constant G will consider only the use of beam balance and simple pendulum method for the experiment
1.7 ORGANISATION OF THE STUDY
This section deals with the organization of the research work in chapters; the chapter one of the research work will cover the background of the study, the statement of problem, the aims and objectives of study, significance and the scope of study, the chapter two will deal with the review of related literature on the gravitational constant G. The chapter three of the research work will cover the areas of materials and method. The chapter four will cover the area of experiment and discussion of results while the chapter five will cover the summary, conclusion and possible recommendation for the research work.
1.8 DEFINITION OF TERMS
Gravity: Gravity, or gravitation, is a natural phenomenon by which all things with mass or energy including planets, stars, galaxies, and even light are brought toward one another.