Why Mirage is posting simple Physics questions on this forum ? Look I suppose this forum is for posting puzzles and not for discussing Physics. His all questions are totally formula based. If someone knows the formula he can solve it. The questions posted on this forum should be like no subjectwise knowledge should be required to solve them.
I would request mirage to stop posting Physics and Chemistry questions and ask some puzzles which are useful to everyone.
People are free to post comment on this. I write what I felt.