Consider an object on a rotating disk a distance r from its center, held in place on the disk by static friction. Which of the following sta

Question

Consider an object on a rotating disk a distance r from its center, held in place on the disk by static friction. Which of the following statements is not true concerning this object:

A) If the angular speed is constant, the object must have constant tangenial speed.
B) If the angular speed is constant, the object is not accelerated
C) The object has a tangenial acceleration only if the disk has an angular acceleration.
D) If the disk has an angular acceleration, the object hasboth a centripetal and a tangenial acceleration
E) The object always has a centripetal acceleration exceptwhen the angular speed is zero

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Vân Khánh 2 months 2021-07-29T21:07:31+00:00 1 Answers 2 views 0

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    2021-07-29T21:08:34+00:00

    Answer:

    A) False

    B) False

    C) True

    D) True

    E) True

    Explanation:

    A) The formula for tangential speed v in term of angular speed ω and radius of rotation r is

    v = \omega r

    So if the angular speed is constant and 0, the tangential speed is also 0. A) is false

    B) False because of the centripetal acceleration:

    a_c = \omega^2 r

    C) True because of the formula for tangential acceleration in term of angular acceleration α is

    a_t = \alpha r

    D) True because same as D), if it has angular acceleration, it would have a tangential acceleration. Also from B) the centripetal acceleration will come with time as soon as angular speed is generated by angular acceleration.

    E) True and same explanation as from B)

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