The acceleration of a particle moving along the circumference of a circle with a uniform speed, is directed

ANS:B - tangentially at that point

"tangentially at that point" in the context of a particle moving along the circumference of a circle, it refers to the direction of the particle's velocity at a specific instant. Imagine a particle moving along the circumference of a circle. At any point along the circle's circumference, the particle has a velocity tangent to the circle at that point. This velocity is purely tangential to the circle's path and is directed along the tangent line to the circle at the specific point where the particle is located. However, while the velocity of the particle is tangential to the circle at that point, the acceleration required to keep the particle moving in a circular path (centripetal acceleration) acts towards the center of the circle. So, while the velocity is tangential to the circle's circumference, the acceleration required to maintain circular motion is directed towards the center of the circle. This is a key concept in understanding circular motion dynamics.