When a body falls freely under gravity, then it moves with a constant
(A) speed (B) velocity
(C) acceleration (D) None
Answers
⚕ Your Answer:
✒ Constant acceleration (Option C)
⚕ Explanation:
Free fall is the motion of an object only under the influence of gravity, neglecting all other forces. An object is in free fall as soon as it is dropped from rest (initial velocity - 0), thrown downward or upward.
- Here, the acceleration is known as Accleration due to gravity which is known as constant acceleration. Its magnitude is denoted by g. The value of g on the surface of earth is nearly 9.8 m/s²
Earth's gravity always pulls downward, so the acceleration of an object in free fall is always downward and constant in magnitude, regardless of the direction of motion of the object.
- If it moving downward, downward acceleration makes it speeds up; and if it moving upward, the downward acceleration slows it down.
⚕ Something more:
Generally, equations of motion are generally applied in constant acceleration motion. Here, in case of free fall, the acceleration due to gravity, it is constant acceleration.
❇ Case 1: When thrown downward (a = g)
- v = u + gt
- h = ut + 1/2 gt²
- v² = u² + 2gh
Here, h is the height from which object is falling.
❇ Case 2: When thrown upward (a = -g)
- v = u - gt
- h = ut - 1/2 gt²
- v² = u² - 2gh
Same, just sign changed because a = -g
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