absolute angular displacement

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Definition

absolute angular displacement is a measure of the total rotation or turning of an object around a fixed axis, without considering its orientation relative to that axis.

History

The concept of absolute angular displacement has been around for centuries. Ancient Greek philosophers such as Aristotle and Archimedes studied the relationship between angular displacement and rotational motion. However, it wasn’t until the 19th century that the modern definition of absolute angular displacement was developed.

Mathematical Definition

absolute angular displacement (θ) is defined as the integral of the product of the angular velocity (ω) and time (t), minus the integral of the product of the linear velocity (v) and time. Mathematically, it can be expressed as:

θ = ∫(ω dt)

or

θ = −∫(v dt)

This definition assumes that the object is rotating without any changes in its speed or direction.

Practical Applications

absolute angular displacement has numerous practical applications in various fields such as:

Key Points

Definition of Terms

  • Angular Displacement: The total rotation or turning of an object around a fixed axis, without considering its orientation relative to that axis.
  • angular velocity: The rate of change of angular displacement with respect to time, measured in radians per second (rad/s).
  • linear velocity: The rate of change of position with respect to time, measured in meters per second (m/s).

Formula

θ = ∫(ω dt)

or

θ = −∫(v dt)

where θ is the absolute angular displacement, ω is the angular velocity, and v is the linear velocity.

Examples

Example 1: Calculating absolute angular displacement

Suppose a ball is thrown upward with an initial velocity of 20 m/s. Assuming constant acceleration due to gravity (9.8 m/s²), calculate the absolute angular displacement after 2 seconds:

θ = ∫(ω dt) = ω0 t = (9.8 m/s²)(2 s) - (0 m/s²)

θ = 19.6 rad

Example 2: Calculating Linear Displacement

Suppose a car accelerates from 0 to 50 km/h in 4 seconds, using constant acceleration due to gravity (9.8 m/s²). Calculate the linear displacement after 4 seconds:

v(t) = ω0 t + ∫(ω dt) = 0 m/s + (9.8 m/s²)(t) - (0 m/s²)

v(t) = 38.4 m/s

s(t) = ∫(v dt) = s0 t + ∫(v dt) = 0 m + (38.4 m/s)(t) - (0 m/s²)

s(t) = 38.4t m

The absolute angular displacement is given by:

θ = θ + s = 19.6 rad + 38.4t

Conclusion

absolute angular displacement is a fundamental concept in physics and engineering, describing the total rotation or turning of an object around a fixed axis. It has numerous practical applications across various fields. By understanding the mathematical definition and practical uses of absolute angular displacement, we can better appreciate the importance of rotational motion in everyday life.

References

  • Aristotle: “De Anima” (On the Soul)
  • Archimedes: “measurement of a circle
  • Newton’s Laws of Motion: Isaac Newton
  • Kerstiens, W. and G. E. Janssen: “Mathematics for Engineers: Concepts, Principles, and Methods”

Note

The information provided is based on the available data up to December 2023. For more recent updates and accurate calculations, please consult reputable sources or professional experts in relevant fields.