# Vertical Motion Question

## Homework Statement

A ball is thrown vertically from the edge of a cliff. It rises 10 m above the cliff, then falls 50 m below the cliff.
Find the inital velocity and determine the time the ball was in the air.

## Homework Equations

(v final )^2 - (v initial)^2 = 2a (delta y)

## The Attempt at a Solution

I'm not sure if I should use 10 or 60 m for the displacement in this equation.

I used 60 m and got v inital = 34. 292 m/s.

Hootenanny
Staff Emeritus
Gold Member

## Homework Statement

A ball is thrown vertically from the edge of a cliff. It rises 10 m above the cliff, then falls 50 m below the cliff.
Find the inital velocity and determine the time the ball was in the air.

## Homework Equations

(v final )^2 - (v initial)^2 = 2a (delta y)

## The Attempt at a Solution

I'm not sure if I should use 10 or 60 m for the displacement in this equation.

I used 60 m and got v inital = 34. 292 m/s.
Displacement is a vector with a magnitude equal to the distance between the initial point & final point. In this case your initial point is 0m and your final point is -50m.

tiny-tim
Homework Helper
A ball is thrown vertically from the edge of a cliff. It rises 10 m above the cliff, then falls 50 m below the cliff.
Find the inital velocity and determine the time the ball was in the air.

I used 60 m and got v inital = 34. 292 m/s.

Hi veronicak5678!

I don't get it … what did you use for vfinal?

(and why 60 rather than 40?)

Hint: you need at least one known v … so what y must you use?

I used 0 for v final. And I used 60 because it travels 10 above, then 50 below. So I should just use 50 for delta y?

tiny-tim