# Homework Help: A ball is thrown above th house

1. Sep 28, 2007

### AvrGang

1. The problem statement, all variables and given/known data
Here is a question that I spent 1 hour trying to find a solution but I din't come up with any solution, so plz give me any hint you know to solve this problem.

The question is:
You're 6.0 m from one wall of a house. You want to toss a ball to your friend who is 6.0 m from the opposite wall. The throw and catch each occur 1.0 m above the ground.

A.What minimum speed will allow the ball to clear the roof?
B.At what angle should you toss the ball?

Help me with the first part only, I can find the second part by myself.

2. Relevant equations

3. The attempt at a solution
I found the hight from where the ball is caught(1.0m above the ground) to the highest point of the roof where the ball clear the roof. The hight is 3 m
but Ididn't find an equation to find the velocity.

Last edited: Sep 28, 2007
2. Sep 28, 2007

### AvrGang

I'm online for any discussion

3. Sep 28, 2007

### rocomath

attempt attempt? show your so called stupid attempt, nobody is going to laugh at you, but we'd respect you for showing your work :)

i'm working on it right now, but someone who is better at physics might help you if you show some work

4. Sep 28, 2007

### AvrGang

ok here is my attempt:

I found the hight from where the ball is caught(1.0m above the ground) to the highest point of the roof where the ball clear the roof. The hight is 3 m
but Ididn't find an equation to find the velocity.

5. Sep 28, 2007

### hotvette

Show us the equation(s) you used to find the height.

6. Sep 28, 2007

### AvrGang

i found it using the graph in my book

I'll try to post the graph

7. Sep 28, 2007

### hotvette

No need. Isn't the idea to use appropriate equations of motion (in this case for a projectile) to solve the problem? Or, are you suppose to just analyze the graph, which I presume is a graph of distance vs time? Remember the definition of velocity?

Last edited: Sep 28, 2007