Torque on a horizontal axis

[Andrea Vironda]

Hi,
I'm making some confusion about statical and dynamic behavior.
if i have a body distant from the rotational axis, i have a static torque for maintaining it on position (i suppose $\vec g \perp \vec r$).
But if a supply more torque i accellerate the body. How can i quantify this accelleration? it will be not constant because $\vec g$ is no more perpendicular to $\vec r$.
i would obtain $C(\theta)=mg(\theta)r+I\ddot \theta$. How can a motor mantain a constant accelleration?

 

[Nidum]

How can a motor mantain a constant accelleration

I don't understand the problem - a suitable choice of motor and control system will do anything that you want it to do .

Is your question really meant to be about how to determine the variable driving torque needed to maintain a constant angular acceleration ?

 

[Andrea Vironda]

I don't understand the problem - a suitable choice of motor and control system will do anything that you want it to do .

Is your question really meant to be about how determine the variable driving torque needed to maintain a constant angular acceleration ?

i would to know if my expression in $C(\theta)$ is correct

 

[Dr.D]

What do you intend your expression C(theta) to represent?

Where does a motor enter into the problem as originally described?

 

[Andrea Vironda]

hi, $C$ is a torque, $coppia$ in italian language. It's the torque expression as $f(\theta)$

 

[Dr.D]

You need to understand that g is not a function of theta; g is a constant. What you need is the component of g that acts perpendicular to the radius. Draw a diagram with labels and it should all become clear.