Angular Displacement in Rotational Dynamics

In summary, rotational dynamics uses the angle as the base quantity instead of arc length because angular displacement is easier to measure and does not depend on a chosen radius. Using arc length would require indicating the corresponding radius, making it less practical in this context.
  • #1
cscott
782
1
Why do we use the angle as the base quantity in rotational dynamics instead of, perhaps, arc length? Is it because angular displacement is easier to measure? Would it make any sense to use arc length?
 
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  • #2
Arc length depends on the radius that you choose, so you always have to indicate the radius you are using that corresponds to that arc length. Angular displacement doesn't.

Zz.
 
  • #3
ZapperZ said:
Arc length depends on the radius that you choose, so you always have to indicate the radius you are using that corresponds to that arc length. Angular displacement doesn't.

Zz.

Oh, that makes sense. Thanks!
 

1. What is angular displacement?

Angular displacement is a measurement of the change in the angle of an object's position in rotational motion. It is typically measured in radians or degrees.

2. How is angular displacement different from linear displacement?

Angular displacement measures the change in angle, while linear displacement measures the change in distance. Angular displacement is specific to rotational motion, while linear displacement can occur in both rotational and linear motion.

3. How is angular displacement related to rotational velocity and acceleration?

Angular displacement, rotational velocity, and rotational acceleration are all related through the equations: ω = Δθ/Δt and α = Δω/Δt. This means that angular displacement is directly proportional to rotational velocity and the change in rotational velocity is directly proportional to rotational acceleration.

4. How does angular displacement affect an object's moment of inertia?

Angular displacement has a direct relationship with an object's moment of inertia. As the angular displacement increases, the moment of inertia also increases. This means that it becomes more difficult to change the rotational motion of an object with a larger moment of inertia.

5. How is angular displacement used in real-world applications?

Angular displacement is used in various real-world applications, such as in the design and analysis of rotating machinery, vehicles, and structures. It is also used in fields such as robotics, aerospace engineering, and physics to study the motion of rotating objects.

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