About
an open source physics at Singapore simulation based on codes written by Anne Cox, Wolfgang Christian, Francisco Esquembre and Loo Kang WEE.
more resources can be found here
http://iwant2study.org/ospsg/index.php/interactive-resources/physics/02-newtonian-mechanics/08-gravity

Introduction
Every object sets up a gravitational field and thus potential around itself due to its mass. When two objects enter each other’s gravitational fields, they will be attracted towards each other.
Hence, a gravitational field is a region of space in which any object that lies in it experiences a gravitational force towards the object that creates the field, due to its mass.
The intent of these activities is to allow students be like a student-scientists and collect their own data to form an understanding of potential energy.
The test mass (green) is at r = 100 m, observe and record the value for U r=100 = -6.67 x10-11 J
Click play and pause the model when r = 90 m, record the value of U r=90 = ____________ J
Click play and pause the model when r = 80 m, record the value of U r=80 = ____________ J
Click play and pause the model when r = 70 m, record the value of U r=70 = ____________ J
Click play and pause the model when r = 60 m, record the value of U r=60 = ____________ J
Click play and pause the model when r = 50 m, record the value of U r=50 = ____________ J
Click play and pause the model when r = 40 m, record the value of U r=40 = ____________ J
Click play and pause the model when r = 30 m, record the value of U r=30 = ____________ J
Click play and pause the model when r = 20 m, record the value of U r=20 = ____________ J
Calculate the change in U from r = 100 to r = 50.
Answer is about ΔU=-[6.67x10-11(1)(100)50-6.67x10-11(1)(100)100]=-6.67x10-9J
Check the "your model" checkbox and a teal color line appear. For example if the model is , U=-GmMr, key in -6.67*1*100/abs(r) and observe the closeness of fit of the orange color line (data collected) versus the teal color line (model proposed).
Suggest with reason why you think the model -6.67*1*100/abs(r) is accurate.
Note that the model already has a multiple of x10-11 so there is no need to key it.
This is a Lab that allows the exploration of this in a one dimensional space.



Interesting Fact
This app produce real numbers to coincident with the real world data.

Acknowledgement
My sincere gratitude for the tireless contributions of Francisco Esquembre, Fu-Kwun Hwang, Wolfgang Christian, Félix Jesús Garcia Clemente, Anne Cox, Andrew Duffy, Todd Timberlake and many more in the Open Source Physics community. I have designed much of the above based on their ideas and insights.
This research is supported by the eduLab project NRF2015-EDU001-EL021 , awarded by the Prime Minister Office, National Research Foundation (NRF), Singapore in collaboration with National Institute of Education (NIE), Singapore and the Ministry of Education (MOE), Singapore.
reference:
http://edulab.moe.edu.sg/edulab-programmes/existing-projects/nrf2015-edu001-el021

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