# An object travels in a circular path at constant speed. Which statement about the object is correct? A It has changing kinetic energy. B It has changing momentum. C It has constant velocity. D It is not accelerating.

Mar 17, 2018

$B$

#### Explanation:

kinetic energy depends on magnitude of velocity i.e $\frac{1}{2} m {v}^{2}$ (where, $m$ is its mass and $v$ is speed)

Now, if speed remains constant,kinetic energy doesn't change.

As,velocity is a vector quantity,while moving in a circular pathway,though its magnitude is fixed but direction of velocity changes,so velocity doesn't remain constant.

Now,momentum is also a vector quantity,expressed as $m \vec{v}$,so momentum changes as $\vec{v}$ changes.

Now,as velocity is not constant,the particle must be accelerating, as $a = \frac{\mathrm{dv}}{\mathrm{dt}}$