Suppose a rock on Earth is dropped in a vacuum and has an initial speed of 0 m/s. What is the rock's speed after 2 seconds, in m/s?

There are many different equations which can be used to find acceleration, time, velocity, distance, etc. However, there are three variables we need to take into consideration for this question, initial velocity, acceleration due to gravity, and time.

The equation acceleration = velocity/time, can be used, and we need to remember that on Earth, acceleration due to gravity is calculated to be 9.8 m/s².

So using the equation:

a = v/t

v = a x t

v = (9.8 m/s²) x (2 s)

v = 19.6 m/s

Gravitational acceleration : 10m/s

2 secs, 10m/s x 2

= 20m/s