Is being fired out of a cannon dangerous?

It's all in the preparation. When David Smith Sr made his unique flight across the Mexican-American border this week, it's a fair bet that he had already done his physics homework.

For a start, he probably didn't use gunpowder for the explosion that catapulted him 45m out of a cannon and over a 6m high fence. Allan McPherson, founder of the Blackpool Circus School, says that the firing mechanism for human cannonballs usually works by releasing compressed air. The amount and pressure of the air depends on the size of the person involved and how far they need to go.

Once Smith had emerged from the end of the cannon, his body would act like any projectile (a cannonball, say) and fall in a predictable parabolic curve back to the Earth. Plug in the forces and speeds involved and you can easily work out where the human cannonball will land.

The final bit of skill lies with the performer, says McPherson. Because a person can change their aerodynamic profile (and therefore exactly where they land) by bending their body or sticking their arms out, Smith had to stay straight and rigid to keep to his flight plan. At the right moment, he would then have tucked his upper body into his legs so that he turned and landed on his back.

If the cannon misfires - say there had been a leak in the compressed air supply - there are other things to think about. McPherson says that if the performer reckons they won't reach the net, they can train to land in a different spot. If necessary, they could even angle themselves to land on their feet and roll along the ground to avoid getting killed. Well, that's the theory, anyway.

ncG1vNJzZmivp6x7tbTEoKyaqpSerq96wqikaKuTnrKvr8RoaWloZWTApryOaWhorJiewLixxKSqrJuZmruksdCunKysmaS7tA%3D%3D