Leaf spring is one of a component of the vehicle which is used to vibration damping caused by the force. Some of case that occur in the vehicle namely overload where this case can affect to fatigue life of steel leaf spring. One of method that is use to fatigue life prediction is the high fatigue cycle, and this method can be simulated by a finite element method. The numbers of both elements and nodes that have been used in this research are 6961 elements and 14726 nodes, respectively. The magnitude of the force that is applied to prediction fatigue life of leaf spring are 80 KN, 100 KN, and 200 KN. Based of the finite element analysis, fatigue life of the force 80 KN longer than force 200 KN and 200 KN was obtained which is a desired 10 6 cycle. Also, the critical value of the fatigue life 80 KN is smaller than 100 KN, and 200 KN. As such, the force 80 KN is a recommended as an allowed force which use to vehicle. This value is validated by safety factor analysis where the force allowed as 80 KN with safety factor equal to 2.56.

Abstract.  This study aimed at determining students’ achievement on science process skills  after being taught using guided discovery instruction based on Student Worksheets (LKPD) and also at finding out the influence of the instruction used in this study to the students’ science process skills. This research is a pre-experimental study with a research design that is one shut case study. The population of this study were 123 people who were spread into 4 classes. The sample in this study were 30 people who obtained based on purposive sampling technique. Based on descriptive analysis, it is obtained an average score of student mastery of 83.30 which is greather than minimum score of student’s mastery (KKM) of 75. The hypothesis testing is done using binomial test. Therefore, based on these findings, it can be concluded that the implementation of guided discovery instruction based on student worksheets (LKPD) can affect science process skills.  Keywords: science process skills, guided discovery, student worksheets Abstrak. Penelitian ini bertujuan untuk mengetahui seberapa besar keterampilan proses sains peserta didik setelah diajar dengan menggunakan pembelajaran discovery terbimbing berbasis Lembar Kerja Peserta Didik (LKPD) dan untuk mengetahui adanya pengaruh keterampilan proses sains peserta didik setelah diajar dengan menggunakan metode pembelajaran discovery terbimbing berbasis lembar kerja peserta didik (LKPD). Penelitian ini merupakan penelitian pra-eksperimen dengan  desain penelitian  one shut case study. Populasi penelitian ini sebanyak 123 orang yang tersebar ke dalam 4 kelas. Sampel pada penelitian ini sebanyak 30 orang yang diperoleh berdasarkan teknik pengambilan purposive sampling. Berdasarkan analisis deskriptif diperoleh nilai rata-rata 83,30 yang mana lebih besar dari pada nilai kriteria ketuntasan minimal (KKM) yakni 75. Adapun pengujian hipotesis dilakukan dengan menggunakan uji binomial. Berdasarkan pengujian tersebut dapat disimpulkan bahwa dengan menggunakan metode pembelajaran discovery terbimbing berbasis lembar kerja peserta didik (LKPD) dapat berpengaruh terhadap keterampilan proses sains.  Kata kunci: keterampilan proses sains, penemuan terbimbing, Lembar kerja peserta didik

This study aims to detemine the effect of thickness on the absorption coefficient of acoustic boards from corn waste and coconut fiber with polyester resin adhesive. The procedure used is used in the research carried out by making acoustic boards with two types of samples, which are fine chopped materials and materials that have been roughly cut with a thickness of 0.7 cm, 1.0 cm and 1.5 cm and measure the coefficient absorption of the thickness of the acoustic material board. The frequency value used is 200 Hz, 250 Hz, 500Hz, 1000 Hz, 2000 Hz and also 4000 Hz. Based on the results of research conducted, it is found that the absorption coefficient value of straight-line coefficient, where the thicker a material, the smaller the coefficient of absorption. Sound absorption coefficient is good, namely at all thicknesses with a frequency of 200 Hz, 250 Hz and 500 Hz both from fine counts and rough counts. This shows that acoustic boards made of corn husk and coconut fiber can be used as sound absorbers because they have been included in the requirements of the ISO 11654 standard.