# NTNUJAVA Virtual Physics LaboratoryEnjoy the fun of physics with simulations! Backup site http://enjoy.phy.ntnu.edu.tw/ntnujava/

## Misc => Physics Questions => Topic started by: tesla2 on January 07, 2013, 05:14:48 pm

 Title: Internal Doppler or One laser can I measure velocity like this Post by: tesla2 on January 07, 2013, 05:14:48 pm  (http://1.bp.blogspot.com/-2QdCDlfb5BU/UOpwa00dYPI/AAAAAAAAAdo/LOZkyFJvQt8/s1600/FrfL2.JPG)(http://3.bp.blogspot.com/-QAAvQuZjtmI/UOhDTjKm0uI/AAAAAAAAAbU/_g7IkKC_K00/s1600/8x.JPG)GALILEO STARTED WINDOWLESS ROCKET PROBLEMMany authors repeat  below words as a famous problem  ( I copy below words)************************************************************************"  Imagine an observer traveling inside a windowless spaceship moving away from the sun at constant velocity. Galileo asserted that there are no mechanical experiments that can be made inside the rocket that will tell the occupants that the rocket is moving . The question ``are we moving'' has no meaning unless we specify a reference frame (are we moving with respect to that star'' is meaningful). This fact, formulated in the 1600's remains very true today and is one of the cornerstones of Einstein's theories of relativity. "..."Einstein’s theory was based on two key principles:1 The principle of relativity: The laws of physics don’t change, even for objects moving in inertial (constant speed) frames of reference. 2 The principle of the speed of light: The speed of light is the same for all observers, regardless of their motion relative to the light source. (Physicists write this speed using the symbol c.) "**********************************************************************More detail about doppler http://tesla64.blogspot.com/ points 1-4  and drawing = main  idea without calculator :1. Distace laser/sensors = 300 000 km light need 1s to touch sensor 2. Laser turn on/off   time  t=0,1 s  (work time)3. What will register  sensor   - time between (0,1 - 1) s  and after ?4. ENERGY : What if rocket's V is  too fast for sensor long ? to confirm -measure Energy that laser  took  and sensor register(http://3.bp.blogspot.com/-XLK3YGX98Hc/UNV10UiLPnI/AAAAAAAAAVo/iXJD5sHtokQ/s1600/5a.JPG)More detail about laser http://tesla32.blogspot.com/I'm engineer / invetor I looking for job / target >>> http://tesla4.blogspot.com/ Title: Re: Internal Doppler or One laser can I measure velocity like this Post by: AnnieWilliams on December 20, 2013, 03:44:06 pm Thank you for this great idea! I solved my homework.