How Do You Calculate the Initial Speed of the Second Stone?

[kmshowalter]

Homework Statement

A stone is dropped into a river from a bridge 47.0 m above the water. Another stone is thrown vertically down 1.48 s after the first is dropped. Both stones strike the water at the same time. What is the initial speed of the second stone?

Homework Equations

The Attempt at a Solution

What I'm not understanding is how to find the initial velocity of the first stone. I'm pretty sure you need that to figure out the initial speed of the second stone. At first I thought I needed to do 47/1.48s but when I did that I realized I didn't understand what that number would even represent. I know that I need an equation that will give me the time for both stones.

 

[gneill]

Homework Statement

A stone is dropped into a river from a bridge 47.0 m above the water. Another stone is thrown vertically down 1.48 s after the first is dropped. Both stones strike the water at the same time. What is the initial speed of the second stone?

Homework Equations

The Attempt at a Solution

What I'm not understanding is how to find the initial velocity of the first stone. I'm pretty sure you need that to figure out the initial speed of the second stone. At first I thought I needed to do 47/1.48s but when I did that I realized I didn't understand what that number would even represent. I know that I need an equation that will give me the time for both stones.

When something is "dropped" it is assumed to be released from rest. When something is "thrown" it is given some initial velocity.