Physics Olympics?

<p>I'm not exactly sure which forum I should put this under so I put it in here. Anyway, I'm currently trying to think of the best way to undertake my project for the Physics olympics. The goal of the event I'm taking place in is to, "design and build a device that will launch a 2-kg sandbag straight up as far as possible and to catch it before it hits the ground." Additional requirements are, "the sandbag must remain intact and come to rest a measurable distance above the ground." </p>

<pre><code> I'm stuck at the moment and don't have to many ideas on how I should go about this. I was just wondering if any of you had an idea on how I could go about building my device? Also if you could explain to me using physics knowledge why the your idea will work would be very helpful.
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<p>Thank you in advance.</p>

<p>Please, doesn't anyone have some advice?</p>