A body will continue in its state of rest or uniform motion in a straight line, unless acted by some external force. What does this statement represent?
Newton's first law says that if a body is at rest it remain at rest but if a body is moving in uniform linear motion it keep moving on and on and on untill a external force is applied ,so when I slip my book in straight line it stops after 3 s how this is done which force is stopping my book to keep moving .