Physics · Circular Motion & Momentum

In circular motion, linear acceleration (tangential acceleration) can be considered variable due to the continuous change in direction of the velocity vector, even when the speed is constant. This means that while the magnitude of the speed may remain the same, the direction of motion is in constant flux, which results in a changing acceleration vector.

Option A (negative) is incorrect because it misinterprets the nature of acceleration in uniform circular motion. Option B (positive) is also incorrect, as there is no increase in speed in uniform circular motion. Option C (constant) is misleading because it ignores the continuous change in direction, which defines the variable nature of acceleration in circular motion.

Negative acceleration refers to a decrease in speed. However, in uniform circular motion, the speed remains constant while the direction changes, which means the acceleration is not negative.

Positive acceleration indicates an increase in speed. In circular motion with constant speed, the object's speed does not increase, so this option is incorrect.

Constant acceleration implies that the acceleration does not change over time. In circular motion, while speed remains constant, the direction changes continuously, making this option incorrect.

Variable acceleration means that the acceleration can change in magnitude or direction. In circular motion at constant speed, the direction of velocity changes constantly, making the linear acceleration variable.