Seminar Universitas PGRI Semarang, LONTAR PYSICS FORUM 2017

Font Size: 
Kajian Fisika Kontekstual: Payung dan Koefisien Hambatan Udaranya
Akadius Gian, Wahyu Hari Kristiyanto, Debora Natalia Sudjito

Last modified: 2017-10-04


The urgent thing in contextual physics learning was to shift the ideal approach to a realistic approach. In the process of submission and discussion in physics books of mechanics topic in junior or senior high school, particularly in this study was the learning of motion concept, are usually discussed by the concept of idealization that nullifies the air barriers so that it tends to be not contextual. The purpose of this study was to examine the contextual physics with the main focus on the umbrella and its coefficient of air resistance. The final result of this research was a learning design related to air resistance that can be used as an example of contextual learning in schools. The research was conducted by measuring the coefficient of air resistance of 4 umbrellas which have a different area that mounted on a moving motorcycle with a spring balance. The motorcycle speedometer shows the umbrella speed, whether the spring’s balance shown the magnitude of air drag force on the umbrella. The magnitude of air drag force at any given speed was obtained through video recording on speedometer and spring balance that showed in graph f(v) and fitted into linear equations. The gradient of the graph was the value of the air resistance coefficient (b) on the umbrella. The obtained coefficient was used to solve the equation Fs = - b v so that the experiment in this study can be used as a proper example for contextual physics learning about the motion that taking into account the air drag force. The result shows that air resistance coefficient b was linearly proportional to the area of ​​the umbrella cross section A. The learning design was qualitatively tested and can be used as a proper example of contextual learning in schools related to air barriers.

Full Text: PDF