Question

A meter stick is found to balance at the 49.7-cm mark when placed on a fulcrum. When a 41.5-gram mass is attached at the 28.5-cm mark, the fulcrum must be moved to the 39.2-cm mark for balance. What is the mass of the meter stick

Answer 1

Answer:

The value is  $M = 42.3 \ kg$

Explanation:

From the question we are told that

    The first  position of the fulcrum  is  x = 49.7 cm

    The mass  attached is $m = 41.5 \ g$

    The position of the attachment is  $x_1 = 28.5 \ cm$  

    The second position of the fulcrum is  $x_2 = 39.2 \ cm$

Generally the sum of clockwise torque =  sum of anti - clockwise torque

So  

       $CWT = m (x_2 - x_1)$

Here CWT  stands for clockwise torque

       $ACWT = M ( x - x_2)$

So

      $m (x_2 - x_1) = M ( x - x_2)$

=>   $41.5 (39.2 - 28.5 ) = M ( 49.7 -39.2 )$

=>    $M = 42.3 \ kg$