Question

Which of the following is an example of a freely falling body \[?\]
A. A ball thrown downward with a speed of \[30\,m{s^{ - 1}}\].
B. A ball thrown upward with a speed of \[30\,m{s^{ - 1}}\].
C. A ball thrown horizontally with a speed of \[30\,m{s^{ - 1}}\].
D. A ball just dropped from a height.

Answer 1

Hint: A freely falling object is any object moving either upward or downward under the influence of gravity alone. In both cases, the object always experiences the same downward acceleration due to gravity. Hence any object is said to be freely falling when no force is acting other than gravitational force on that object. Then there is no applied force acting on it.

Complete answer:
Since free fall is any motion of a body where gravity is the only force acting upon it. Hence the given ball is falling without any initial velocity. Since, in the first three options the ball is thrown with the initial velocity. But the option is falling from a height without any initial velocity.

Hence the correct option is D.

Note: Note that the acceleration due to gravity is always constant. So, freefall is a special case of motion(uniformly) with constant acceleration; this is true even if its initial velocity may or may not be zero. Also note that a body executing free fall is irrespective of its position.