Question

Assertion made by Newton’s first law of motion that everybody continues in its state of uniform motion in the absence of external force appears to be contradicted in everybody experience. Why?

Answer 1

The resistance offered by air and the friction of surface oppose the motion so the moving bodies have to stop after sometime. Had there been no friction, no force would have been required to keep a body in the state of uniform motion in a straight line (i.e., linear uniform motion).