Centripetal acceleration and circular motion

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SUMMARY

The centripetal acceleration formula |a| = ω²*r indicates that increasing the radius (r) while keeping angular speed (ω) constant results in increased centripetal acceleration. This is counterintuitive since the velocity vector is consistently turned at the same rate. However, as the radius increases, the linear velocity (v = ω * r) also increases, necessitating a greater centripetal acceleration to maintain circular motion. The relationship between the units of acceleration (m/s²) and circular motion can be understood through the derived forms of the centripetal acceleration equation.

PREREQUISITES
  • Understanding of angular velocity (ω) and its units (radians per second).
  • Familiarity with the concept of linear velocity (v) and its relationship to angular velocity.
  • Knowledge of the formula for centripetal acceleration |a| = ω²*r.
  • Basic grasp of circular motion dynamics and geometry.
NEXT STEPS
  • Explore the derivation of centripetal acceleration from first principles.
  • Study the relationship between angular velocity and linear velocity in circular motion.
  • Investigate real-world applications of centripetal acceleration in engineering and physics.
  • Learn about the effects of varying radius and angular speed on circular motion dynamics.
USEFUL FOR

Students of physics, educators teaching circular motion concepts, and engineers involved in rotational dynamics will benefit from this discussion.

GeneralOJB
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My question is about the centripetal acceleration formula |a| = ω^2*r. If we keep the angular speed constant then why does increasing the radius increase the centripetal acceleration? I don't find this intuitive because the velocity vector is being turned by the same amount each second, if ω is constant.

Also is there an intuitive way to think about how the units (m/s^2) relate to circular motion?
 
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The linear velocity = ω * r. If r increases, then so does the linear velocity. Using the other form for centripetal acceleration:

|a| = ω^2 * r = v^2 / r

If r increases by a factor "c" and ω remains constant, then:

|a| = ω^2 * c * r = (c * v)^2 / (c * r) = c * v^2 / r
 
If ω is constant, the particle has to get from one side of the circle to the other in the same amount of time, ∏ω seconds.

The distance traveled "across the circle" is proportional to r, so it makes sense that the acceleration has to be bigger when r is bigger.
 

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