Given: The particle moves in a circle with constant angular speed.

This is uniform circular motion.

Velocity in uniform circular motion

The instantaneous velocity of a particle moving in a circle is always along the tangent to the circle.

So, statement A is true.

Acceleration in uniform circular motion

For constant angular speed, the speed is constant, but the direction of velocity keeps changing. Hence there is a centripetal acceleration given by $a = \frac{v^2}{r} = \omega^2 r$ and its direction is always towards the centre of the circle.

Therefore, statement C is true.

Is acceleration tangent to the circle?

No. In uniform circular motion, acceleration is radially inward, not tangential.

Tangential acceleration appears only when the speed changes.

Therefore, statement B is false.

Relation between velocity and acceleration

Since velocity is tangent to the circle and centripetal acceleration is toward the centre, the two directions are at right angles.

Hence, $\vec v \perp \vec a$ So statement D is true.

Conclusion

The false statement is: $\boxed{\text{B}}$

Comparison with stored answer

Stored correct answer: B

Our derived answer: B

They match.