Comparative Study Between Smooth and Rough Surface of Frictional Force in Mechanics Laboratory at Wolaita Sodo University

Friction is a resisting force that acts as along the tangent to two surfaces in contact when one body slides over or attempts to slide across another.  Friction plays a major role in our daily life. There are different types of friction: static, kinetic, deformation, rolling and the like. But the aim of this project  is not to study the type of friction, the project focus on comparative study of frictional force between smooth and rough surfaces and to identify the problems that cause the students’ experimental value variation with in the same position of theoretical condition that are discussed in the classroom. For this study, the data were collected by the laboratory experimental values that were recorded by the students in mechanics of frictional forces at W.S.U. This collected data were analyzed in order to compare the experimental value of the smooth surface with the value of the rough surfaces given in the secondary data. Finally, the data is presented to show the causes that hinder the students to find to meet the coherence between the theoretical knowledge and the experimental value Keywords: frictional force, rough, smooth DOI: 10.7176/APTA/79-02 Publication date:September 30th 201

The role of foreign public debt on foreign exchange reserve in SSA countries: Does governance really matters?

AbstractThe debt and reserve are playing a pivotal role in the growth and development of national economies. To examine the role of foreign public debt (FPD) on foreign exchange reserve (FER) the study used a panel data by considering 20 Sub-Saharan Africa (SSA) countries by interacting FPD with governance index across 15 years. The dynamic and static Generalized Method of Moments (GMM) models were utilized after checking the possible assumptions. The GMM model found that FPD, governance index, labour and human capital predicted the FER positively and significantly. While foreign debt augmented with governance predicted the variation of FER negatively and significantly. Therefore, Sub-Saharan Africa’s low performance of foreign debt in enhancing foreign exchange reserve partly attributed to bad governance. Finally, the government of SSA countries should improve their quality of governance to properly utilize FPD to enhance the stock of FER, among others