# Kinematics Question on falling rock

Riju

## Homework Statement

A rock is thrown straight upward from the edge of a 30m cliff, rising 10m, then falling all the way down the base of the cliff.

## The Attempt at a Solution

Well, because the rock was thrown 10m up, and then it came all the way down, I added those quantities (10m+30m) so I got 40m. But since the displacement is the object's initial position to its final position, regardless of the path actually taken, would I have to count the rock before it was thrown? Then the answer would be 30m

Homework Helper
Gold Member

## Homework Statement

A rock is thrown straight upward from the edge of a 30m cliff, rising 10m, then falling all the way down the base of the cliff.

## The Attempt at a Solution

Well, because the rock was thrown 10m up, and then it came all the way down, I added those quantities (10m+30m) so I got 40m. But since the displacement is the object's initial position to its final position, regardless of the path actually taken, would I have to count the rock before it was thrown? Then the answer would be 30m[/B]
You haven't stated what question you are asked.