When a body freely falls, the acceleration is considered to be positive. This is because acceleration is defined as the rate of change of velocity, and in the case of free fall, the velocity of the object increases in the downward direction.
The force of gravity acts on the object, causing it to accelerate downward. Due to the downward acceleration, the velocity of the object increases over time. According to the convention of sign conventions, the downward direction is typically assigned a negative sign. Therefore, in terms of the sign convention, the acceleration due to gravity is considered negative.
However, it's important to note that when we refer to the magnitude of the acceleration (ignoring the sign), the acceleration due to gravity is always positive. The magnitude of acceleration due to gravity is approximately 9.8 meters per second squared (m/s²) near the surface of the Earth. So, the acceleration of a freely falling object is positive in terms of magnitude, but negative in terms of sign due to the downward direction.