The correct option is (c).
Explanation
Free fall refers to the motion of an object where gravity is the only force acting upon it. In this state, the object accelerates towards the center of the Earth with a constant acceleration known as acceleration due to gravity ($g$).
Statement-wise Analysis:
- Statement 1 is Incorrect.
When an object is dropped from a height and falls towards the Earth, it moves in a straight vertical line. While the magnitude of its velocity (speed) increases continuously due to acceleration, the direction of motion remains constant (downwards towards the Earth's center). - Statement 2 is Correct.
The acceleration due to gravity ($g$) is given by the formula $g = \frac{GM}{R^2}$, where $G$ is the gravitational constant, $M$ is the mass of the Earth, and $R$ is the radius of the Earth. This formula does not include the mass of the falling object ($m$). Therefore, all objects, regardless of their mass, experience the same acceleration in the absence of air resistance. - Statement 3 is Correct.
The strict definition of free fall requires that the gravitational force of the Earth is the sole force acting on the object. In practical physics problems regarding free fall, air resistance and buoyancy are neglected.
Key Takeaway:
Free fall is motion under the influence of gravity alone. In a vacuum, all objects fall with the same acceleration ($g \approx 9.8 \, m/s^2$) independent of their mass, moving in a straight vertical line.