If a rock on Earth is dropped in a vacuum and has an initial speed of 0 meters per second What is the rock's falling speed after 2 seconds?

Answer 1

Since there is no air, there is no air resistance so acceleration of free-fall is constant throughout the fall. Thus the first of the four equations of motion can be used.

v = u + at

where v = final velocity, u = initial velocity, a = constant acceleration, t = time of motion

v = 0 + (9.8 m/sec/sec)(2 sec) = 19.6 meters per second.

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Speed = (acceleration) x (time)

Acceleration of a dropped rock = gravity = 9.8 m/s2

Speed = (9.8) x (2) = 19.6 m/sec