There is a metal cube that is any size desired. the contents of the cube is a vacuum of space. there is a tube that is also a vacuum of space that also can be any size desired. The third item is a ball that fits air tight in the tube perfectly at the furthest point from the ball. The ball can be hollow or solid with any weight with the weight evenly distributed throughout the ball. There are no obstructions between the ball an the cube. They are in room temperature with normal ground level air density. Then the furthest point from the cube on the tube is opened up letting in the air. How much force would this give the ball as the air rushes in pushing the ball to try and fill the empty void in the cube? I came up with the idea for this experiment when I was thinking about different ways we could travel into space by using little to no fuel/ thinking of sifi things. If I had an air compressor, chronometer, plenty of scrap metal and a welding kit i could figure it all out on my own.