# Water Cannon

#### ThePlasmaPro

EDIT B: Ok, this is what I did. I got rid of the rest to avoid confusion.

The question: A cannon fires water such that it is a cylinder with a radius of 10 cm, and at an angle of 21.8 degrees. If the water lands 10 km away after 30 minutes, how much force is behind it, and how much pressure is exerted?

I calculated the volume of the cylinder based on the distance traveled, and as the distance upward was about 5.4 km and the distance straight was 10 km, the distance traveled diagonally is about 11357.792 meters. Based on the density of water, I calculated the total mass of all water fired to be 1,427,260 kg. Since the average velocity would be 6.31 m/s (the distance over the total time) I found that the average acceleration would be 0.0035 m/s^2, but since it has to overcome gravity I added 9.82 m/s^2 to get 9.8235 m/s^2 which means the force exerted was 14,020,688.61 Newtons which gives a pressure of 446.3 MPa.

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#### oz93666

This makes no sense .... 314 tonnes of water!! travels up 1.8 meters yet travels 10km horizontally ! ...only moving at 10m/sec???