Torque and Statics Balance Problem

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
1 reply · 5K views
lemonlimesoap
Messages
4
Reaction score
0

Homework Statement



Two pans of a balance are 50cm apart. If the fulcrum is displaced by 1cm what percentage is the true weight marked up?

Homework Equations



T=rFsinθ
F=mg

The Attempt at a Solution


I solved for torque of the fulcrum in a hypothetical situation where a mass of 1g is on one end and a mass of 2g on the other

First with the fulcrum in the center making the lever arms 25cm
T=T1+T2

T=7.3575Nm

then with the displaced fulcrum by 1cm. Making the lever arms 24cm and 26cm

T=7.4556Nm

finally i just did percent error

(7.4556Nm-7.3575Nm)/7.3575Nm *100= 1.3%

I'm pretty sure this is wrong since I was just winging it.
 
Physics news on Phys.org
hi lemonlimesoap! :wink:
lemonlimesoap said:
Two pans of a balance are 50cm apart. If the fulcrum is displaced by 1cm what percentage is the true weight marked up?

I solved for torque of the fulcrum in a hypothetical situation where a mass of 1g is on one end and a mass of 2g on the other

nooo :redface:

you're not being realistic about the way a balance works …

a balance works by being balanced

you put an unknown mass in one pan, and known masses in the other pan until the torques are equal

so start again, with 1g in one pan, and m in the other pan …

what is m ? :smile: