- #1

Erenjaeger

- 141

- 6

## Homework Statement

**Concept Simulation 2.3**provides some background for this problem. A ball is thrown vertically upward, which is the positive direction. A little later it returns to its point of release. The ball is in the air for a total time of 8.21 s. What is its initial velocity? Neglect air resistance.

[/B]

## Homework Equations

x

_{f}=x

_{o}+v

_{o}+1/2at

^{2}[/B]

## The Attempt at a Solution

known values

x

_{f}= 0 because it comes back to where it was released from

x

_{o}= 0 because initial displacement is going to be 0

a = -9.8m/s

^{2}

t = 8.21 s

so couldn't you solve by using the kinematic formula

**x**

and then solving for v

leaving you with -v

and because both the initial displacement and final displacement are 0

-v

so -v

which gives me -330.62 which would be just 330.62m/s but it is incorrect. pls helpp[/B]

_{f}=x_{o}+v_{o}+1/2at^{2}and then solving for v

_{o}leaving you with -v

_{o}=x_{o}+1/2at^{2}-x_{f}and because both the initial displacement and final displacement are 0

-v

_{o}= 1/2 at^{2}?so -v

_{o}=-9.8⋅8.21^{2}which gives me -330.62 which would be just 330.62m/s but it is incorrect. pls helpp