- #1

- 138

- 0

## Homework Statement

A cannon is aimed at a target located 72m away from the cannon and 20m above the ground. The cannon ball, when fired, will have the initial speed of 32m/s, but it has to clear a 13m wall between the cannon and the target as, shown. At what angle should the cannon be fired?

**Diagram attached

## Homework Equations

Dy=(Voy)(t)+(1/2)(a)(t)

^{2}

Vx=Dx/t

## The Attempt at a Solution

I have tried to do this question many different ways, but I have not been able to find the correct answer.

Here is what I have tried:

For the first wall Dx= 15, Dy=13, Vx=32cos([tex]\theta[/tex]) Voy=32sin([tex]\theta[/tex])

and since V

_{x}=D

_{x}/t ,D

_{x}/V

_{x}=t then t=15/32cos([tex]\theta[/tex])

D

_{y}=V

_{o}t+1/2(a)(t)

^{2}

13=(32sin([tex]\theta[/tex])(15/32cos([tex]\theta[/tex])+(1/2)(-9.8)(15/32cos(theta)

^{2}

I am going to stop here for help because I don't think I am doing this correctly.

Thank you! =)