Final answer:
Tangential acceleration refers to changes in the speed of an object moving along a circular path, not its direction. It is measured tangent to the circular path, while centripetal acceleration, which affects direction, points inward toward the circle's center.
Step-by-step explanation:
The tangential acceleration corresponds to a change in the speed of an object in motion along a circular path, but it does not alter the direction in which the object is moving. In other words, tangential acceleration involves changes in the magnitude of velocity. This is opposed to centripetal acceleration, which alters the direction of the velocity towards the center of the circle but does not change its magnitude.
When an object experiences tangential acceleration, this usually indicates that it is speeding up or slowing down in the direction tangent to the circle. This is in contrast to centripetal acceleration, which is always directed radially inward. Both accelerations are perpendicular and independent of each other. In scenarios where both types of acceleration are present, the total acceleration is the vector sum of the tangential and centripetal accelerations.
To address the options provided in the question, tangential acceleration does not correspond to a change of velocity direction perpendicular to the radius of the circle (option 1) nor to a change of speed pointing towards the center of the circle (option 2). Instead, it refers to changes in the speed along the tangent to the circle's path.