Question

A meter stick is found to balance at the 49.7-cm mark when placed on a fulcrum. When a 44.0-gram mass is attached at the 24.5-cm mark, the fulcrum must be moved to the 39.2-cm mark for balance. What is the mass of the meter stick?
________g

Answer 1

Here, the torque from the 44 gm mass must equal the torque due to the weight of the meterstick.

Accordingly,

W1 d1 = W2 d2

where W indicates the weight of the first and second objects, and d1, d2 are the distances of these masses from the pivot point at 39.2 cm

Now, suppose object 1 is the mass and object 2 is the stick,

So, we have -

0.044kg*9.8m/s/s*(0.392m-0.245m) = W2 (0.497m-0.392m)

=> 0.06338 = W2*0.105

=> W2 = 0.6036 N

So, m2 = W2/g = 0.6036/9.8 = 0.061594 kg = 61.6 g