# Projectile trajectory problem with constraint

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1. Jan 19, 2016

### jacksmith2296

1. The problem statement, all variables and given/known data
http://imgur.com/RDMG4Pj [Broken]

The ball goes through the hoop NOT at the peak, but rather on it's downward path. It's asking for the total x-displacement, launch angle (theta), and the total flight time. It must me solved WITHOUT using the range formula. The landing point is also .25 meters up, so it lands at the same height it was launched from.

2. Relevant equations

3. The attempt at a solution
I'm completely lost without theta; thanks for your help.

Last edited by a moderator: May 7, 2017
2. Jan 19, 2016

### SteamKing

Staff Emeritus
Why can't you write the regular projectile motion equations? That's where the range formula ultimately comes from.

You treat the launch angle as an unknown to start with, and then you analyze your equations to see if the end of the trajectory satisfies the conditions of going thru the hoop and landing 0.5 m down range at the indicated height. You can always treat this like a game of Battleship, where you guess values of the initial angle and see if the ball hits the target. A problem like this could easily be set up on a spread sheet.

Last edited by a moderator: May 7, 2017
3. Jan 19, 2016

### jacksmith2296

Will you please work it out? I'm honestly just lost, and I think I'd understand better if I could look at the answer and work my way through.

4. Jan 19, 2016

### Staff: Mentor

Sorry but that's not allowed by the forum rules. Helpers are not allowed to completely solve homework problems for other members.

They can provide hints and suggestions, or point out errors or where the chosen method has gone off-track, but they can't do your work for you.

Edit: Please note that I've changed the thread title so that helpers can better recognize the subject matter of the problem.

5. Jan 19, 2016

### SteamKing

Staff Emeritus
Sorry, that's against the rules for the HW forums here at PF. You've got to show some effort at solving your own HW problems.

6. Jan 19, 2016

### jacksmith2296

Sorry I really didn't know