Clock Spring Torque: Understanding Input and Output Torque in Winding Mechanics

[John_tawil]

I'm winding up a clock spring from the outside and release from the inside. Is the input torque = to the output torque?

How would i go about setting up this problem

 

[K^2]

Has to be. Imagine that you are just holding the wound spring from inside and outside. If the two torques don't cancel each other out, there is a net torque on the spring. If there is net torque, it has angular acceleration. But you are holding the spring, so it's not accelerating. Therefore, the two torques are equal.

 

[John_tawil]

THank you

 

[sophiecentaur]

Has to be. Imagine that you are just holding the wound spring from inside and outside. If the two torques don't cancel each other out, there is a net torque on the spring. If there is net torque, it has angular acceleration. But you are holding the spring, so it's not accelerating. Therefore, the two torques are equal.

I just love those Null Arguments. Bomb proof and take care of all counter intuitive worries.