Answers

2014-06-08T11:06:15+08:00
The pen is at rest but there are forces acting upon that pen. For question number 2 of that activity, The pen fell down because of the face of gravity. For the situation 2. The book is at rest but there are forces acting upon that book. To make the book move it has to be either pushed or pulled.
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2014-06-08T11:08:38+08:00
The pen by a piece of string hanging is at rest. 
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