Some Physics HW :)?

Question

I am lost and need help. There are 4 steps to this but hopefully if i get this, I will be able to get the rest. 

Assume you have 3 different items weighing 3 different amounts (kg), a shoe- 0.3 kg, a washer- 0.003 kg, and a spoon- 0.045 kg. You now get a 50 cm string and swing the object around for 10 seconds. Shoe does 11 revolutions, spoon does 16 revolutions and the washer does 21 revolutions. Now calculate the speed and centripetal acceleration.

Answer 1

Favorite Answer

   First up... don't forget to choose a  BEST  answer... !!

speed, that is tangential velocity,  v,   is  :  

       v =  ( 2πr ) * ( # rev )  /  t

All the objects have the  same  value for  2πr,  just convert   r  to meters instead of cm before  any calculations .

  Total distance each moved is  ( 2πr)(# rev)  , so each has a different value here.

So  you can now  find  the speed of each [ which is just the magnitude of  v using eqn above ] .

Centrip force =  mv^2  / r    so  centrip. accel,  a  , is:

     a  =  v^2 / r    again  use  r in meters, and  your  v's   from  part a)