2020 · Q1
Which one of the following statements for an object falling freely under the influence of gravity is correct?
general-sciencephysics-mechanics
- AZero acceleration always implies zero velocity
- BZero acceleration has no relation with the velocity of the object
- CZero velocity at any instant necessarily means zero acceleration at that instant
- DAcceleration is constant all throughout the free fall
Explanation
In free fall the only force acting is gravity, so the acceleration equals g (about 9.8 m/s² downward) at every instant — constant throughout the fall. Zero acceleration does not imply zero velocity: a body in uniform motion has zero acceleration with finite velocity, ruling out A and B. Statement C is false too: at the top of a vertical toss the velocity is momentarily zero while the acceleration remains g. Hence D is the only correct statement.