I am in high school and my textbook says that

"a body is said to be in pure rotation if every point on that body moves in a circular path about a fixed axis of rotation"

but my doubt is that at any moment, I can define a linear velocity as $V=R\omega$ for any particle of that body, where $R$ is the distance of the particle from the axis of rotation.

but as velocity is defined in straight line motion then how can we say that the object is rotating?


Notice, $V=R\omega$ is the linear or tangential velocity of any particle of a body rotating at angular speed $\omega$ at a particular instant of time $t$ because the tangential velocity $V=R\omega$ keeps on changing in direction from instant to instant while the magnitude $R\omega$ is constant if angular velocity $\omega$ of rotating body is constant.

Therefore, every point of a rotating body has a linear or tangential velocity at a every instant of time. A body moving at a velocity $V$ along a straight line can also be assumed to be moving on circle of ideally infinite radius.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.