Which of the following statements is/are NOT true about an object moving in uniform circular motion? A. The speed of the object remains constant. B. The velocity of the object remains constant. C. The direction of the object's velocity changes continuously.
Only B
In uniform circular motion an object moves along a circular path covering equal distances along the circle in equal intervals of time. Speed is a scalar (magnitude only), while velocity is a vector with both magnitude and direction.
Statement A is true: equal distances in equal times means the speed, the magnitude of the velocity, stays constant.
Statement C is true: at every point the velocity is along the tangent to the circle, and the tangent keeps turning as the object goes round, so the direction of velocity changes continuously.
Statement B is not true: since the direction of velocity changes at every instant, the velocity itself changes even though its magnitude does not. This change of velocity is why uniform circular motion is accelerated motion, with the acceleration directed towards the centre.
So the only statement that is NOT true is B.
Hence, Only B.
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