## Thursday, December 31, 2009

### Irodov Problem 1.369

Without loss of generality let us assume that the observer is moving at a speed with velocity v along the positive x-axis. As seen by the observer, the body is moving along the negative x-axis with a speed v. Let be its density be .

Consider an infinitesimally small cuboidal piece of the body of dimensions dx, dy and dz. The mass dm of this infinitesimally small piece is given by,

As seen by the observer, the mass of the inifinitesimally small cuboid would be

Further, also as seen by the observer, the cuboid would appear to have shrunk along the x dimension to .

Let the density of body as seen by the moving observer be then we have,

Rajkumar said...

thank you

Rajkumar said...

thank you

gaurav said...

i am trying for iit do i neeed to solve irodov as i can manage hc verma very well

Krishna Kant Chintalapudi said...

Please solve Irodov problems because they are fun to solve not because they are like a bad medicine to be gulped down the throat.

I took IIT-JEE 18 years ago. In our days solving Irodov was a must to do reasonably well on the Physics paper.