Physics doubts

Subject: Physics doubts Wed Feb 20, 2008 7:12 pm

1. A man rowing upstream is at rest with respect to the shore. Is he doing work?

2. State 2 conditions for formations of pure spectrum

Subject: Re: Physics doubts Thu Feb 21, 2008 12:17 pm

1. he is not doing work wid respect 2 the shore bcoz der is no displacement.however he is doing work wid respect to the stream

Subject: Re: Physics doubts Sat Feb 23, 2008 10:35 pm

wat do you mean by doing wokr against stream....do you mean that negative work is bieng done as angle betweeen force and displacement is 180

Active member

2. State 2 conditions for formations of pure spectrum

ans:condition 1: A narrow parallel beam of white light should be made incient on the prism.
condition 2:the prism should be placed in the position of minimum deviation
condition 3:the emergent parallel beam should be focussed on the screen

Subject: Re: Physics doubts Wed Mar 12, 2008 11:36 pm

The work done against stream is neutral .You cannot take it as retardation as there is no displacement.

Subject: Re: Physics doubts Sun Mar 22, 2009 7:49 pm

The person is doing +ve work against the stream. As some of you said, here the force and displ are not opposite. they are in the same direction. ( wrt a person on the bank it appears to be zero. but it is only imagination.)