A 1 m radius circular disk rotates at constant angular velocity, so that it takes 1.2 s for a full rotation. What is the normal or centripetal acceleration of the external points of its periphery?


Since the angular velocity is constant and the trajectory of any point is circular we have a uniform circular motion or u.c.m.


R = 1 m
T = 1.2 s


If it takes 1.2 s for a full rotation, the disk turns with a period T=1.2 s. From this period, we can calculate the angular velocity of the disk:

ω=2πTω=2π1.2ω=1.67π rad/s

Considering the definition of normal or centripetal acceleration, we can calculate its value using the following expression:

an=v2R=ω2·R an=(1.67π)2·1 an= 27.52 m/s2

Formulas worksheet

These are the main formulas that you must know to solve this exercise. If you are not clear about their meaning, we recommend you to check the theory in the corresponding sections. Furthermore, you will find in them, under the Formulas tab, the codes that will allow you to integrate these equations in external programs like Word or Mathematica.

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