Physics 150 Lab

Department of Physics & Astronomy

Undergraduate Labs

One-­‐Dimensional  Motion  

The  physical  quantities  position,  displacement,  velocity  and  acceleration  are  the  basis  of  understanding  

objects   in   motion.   These   quantities   are   useful   at   all   length   and   time   scales   and   are   applied   to  

understand  the  motion  of  orbits  of  stars  in  a  galaxy,  the  rotation  of  gears  in  a  machine,  the  flow  of  red  

blood   cells   in   an   artery   and   the   movement   of   atoms   in   a   molecule.   Position   ,   velocity     and  

acceleration    are  related  by  

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This  means,  the  slope  of  an    vs.    graph  is  the  velocity  in  the   -­‐direction  and  the  slope  of  a    vs.    graph  

is  the  acceleration  in  the  -­‐direction.  The  motion  of  an  object  can  be  recorded  in  real-­‐time  through  the  

use  of  a  motion  sensor  or  a  video  camera.  We  will  be  using  both  in  this  lab.  

Our  motion  sensor  sends  out   short  ultrasonic  pulses  (sound  waves  that  are  inaudible  to  humans)  that  

are   reflected   by   an   object   a   distance     away   from   the   sensor.     By   measuring   the   time   it   takes   for   an  

emitted  pulse  to  reflect  off  of  an  object  and  return,  the  sensor  is  able  to  measure  the  position  ,  of  the  

object  as  a  function  of  time.  From  this  data,  a  computer  is  used  to  calculate  the  velocity  and...