Answers

2014-06-02T20:40:22+08:00
Friction and force. Without force, there is no motion and without friction one cannot move from one place to another. 
0
2014-06-02T20:45:36+08:00
Force is needed for an object to move. all massive object have inertia, which is the tendency of an object to remain at rest if it is at rest or to remain in motion  at constant speed along the strait line.
0