Linear air track is often used in physics learning for linear motion experiments because it can reduce friction between objects with trajectories. However,  the use of air tracks for motion experiments in schools often does not care about aspects of air drag, so the purpose of this study is to calculate the air friction contained in the air track and as an offer of enrichment experiments at senior high school. The research method used is an experimental method that uses a set of air track experimental devices consisting of trajectors, carts, blower, and time counters with light sensors. Cart objects with a mass of 120.02 gram is given the initial velocity variation 12.272 cm/s, 16.286 cm/s and 24.599 cm/s. Then the time recorded when the cart crosses the distance of 10 cm to 110 cm at intervals of 10 cm. This experiment is conducted in the Integrated Science Laboratory, Faculty of Mathematics and Natural Sciences, Universitas Negeri Semarang. The second Newton law has been derived to obtain a special exponential function, so the relation between distance and time is obtained. The non-linear relation between distance and time shows the effect of air drag. Then, fitting the graph of the distance and time relation so that the air drag constants obtained are (10.6 ± 0.1) gram/s, (10.6 ± 0.2) gram/s, and (11.1 ± 0.2) gram/s. The results of the air drag constants obtained can be additional data as a factor affecting experiments using linear air track and can be enrichment experiments at senior high school laboratory.

Kelurahan Jatirejo di Kota Semarang merupakan salah satu wilayah yang memiliki permasalahan sampah rumah tangga. Namun kegiatan pengelolaan sampah berbasis masyarakat terkendala oleh waktu dan biaya. Teknik pengomposan dengan metode takakura dapat menjadi solusi dalam pengelolaan sampah rumah tangga di Kelurahan Jatirejo, Kota Semarang. Berangkat dari hal tersebut, kami selaku tim pengabdian melalukan kegiatan pelatihan pembuatan kompos menggunakan metode takakura sebagai solusi penanganan sampah di Kelurahan Jatirejo. Tahapan dalam kegiatan pengabdian ini terdiri dari tahapan persiapan, sosialisasi dan praktik pembuatan kompos. Pada tahapan persiapan, tim pengabdi menggunakan EM4 dalam pembuatan kompos berdasarkan studi literatur. Selanjutnya, tim pengabdi melakukan kegiatan sosialisasi dan praktik pembuatan kompos dengan metode takakura. Setelah kegiatan praktik, para peserta tertarik untuk menerapkan pengomposan dengan metode takakura ditempat tinggal masing-masing. Pengetahuan tentang pemanfaatan sampah rumah tangga bagi ibu-ibu Kelurahan Jatirejo juga semakin berkembang melalui kegiatan pengabdian pelatihan pembuatan pupuk kompos dengan metode takakura. Untuk kegiatan selanjutnya, perlu diuji bagaimana tingkat partisipasi masyarakat Kelurahan Jatirejo dalam pengelolaan sampah berbasis kompos dengan metode takakura. Jatirejo Village in Semarang City is one area that has household waste problems. However, community-based waste management activities are constrained by time and cost. Composting techniques using the takakura method can be a solution to managing household waste in Jatirejo Village, Semarang City. Based on that problem, we as a service team conducted composting training activities using the takakura method to handle waste in Jatirejo Village. The stages in this service activity consist of preparation, socialization and the practice of making compost. In the preparation stage, the service team used EM4 in composting based on a literature study. Furthermore, the service team carried out socialization activities and the practice of making compost using the takakura method. After the practical activity, the participants were interested in applying compost using the takakura method in their respective places of residence. Knowledge related to the use of household waste for women in Jatirejo Village is also growing through service activities for making compost fertilizer using the takakura method. For the next activity, it is necessary to examine how the level of community participation in Jatirejo Village in compost-based waste management using the takakura method is needed.

The Women Farmer Group in Semarang was established in 2013, and it has been developing small businesses in the processing of local fresh milk into various snack products. However, the selling value has not reached the optimum results since it faces a problem in packaging quality. Therefore, as one of the goals of Tridarma of Indonesian higher education which have directed the university to care about problems in society, an accompaniment to the business was carried out for improving the quality of product packaging. There were three activities conducted, i.e.a, training; re-designing; and monitoring. The results of the community service showed that the program was highly effective to enhance the understanding of Women Farmer Group members on the importance of product packaging as a strategy of marketing proved by the results of the average posttest score at 80.55. Product testing to consumers shows that the new packaging could increase consumer buying interest in comparison to the old one. Also, with the new packaging, the non-preservative snacks could have a longer storability compared to the old packaging. In this community service activity, an empowerment model can be obtained and can be further developed.

The purpose of this study was to analyze the capacity of the reservoir to the change in land use around the Unnes campus. The research method used is the flood hydrograph routing method in the reservoir using the Storm Water Management Model (SWMM) program to obtain the maximum capacity of the reservoir flood discharge, after which a comparison of the planned flood discharge of the resevoir to the flood discharge in the existing conditions of the reservoir is carried out to assess the capacity of the Unnes reservoir against land use change. Based on the results of the study, it was found that there was a change in the bottom depth of the reservoir at the beginning of the planning was 4.00 meters and in the current condition it became 3.00 meters, which means that the capacity is reduced by 1.00 meters with the ability to pass the flood discharge inflow which is still adequate and there is no overflow of flood.