A stone is dropped from a building, and 2 seconds later another stone is dropped. How far apart are the two stones by the time the first one has reached a speed of 30 m/s?

Options

A. 80m
B. 60m
C. 20m
D. 40m

Explanation

To solve the problem, we need to find out how far apart the two stones are when the first stone reaches a speed of 30 m/s. Let's break this down step by step.

### Step 1: Determine the time taken for the first stone to reach a speed of 30 m/s.

We can use the equation of motion:
\[ v = u + at \]
Where:
- \( v \) = final velocity (30 m/s)
...