## Saturday, November 10, 2012

### Physics of a Flyboard

By Alison Rosser

This is honestly one of the coolest videos I’ve ever seen. I never thought the idea of using a jetpack board to fly over the water was even possible! The newest watersport is known as Flyboarding, and all you need is \$9995 and a jet ski! With a lesson lasting a couple hours, you too can be flying over the water doing somersaults in the air and impressing all your friends! To be quite honest I thought something like this was only seen in science fiction movies and never in real life! The science behind the flyboard is surprisingly simple.
First off: the mass of an average person is 70 kg and the weight of the flyboard equipment is less than 100 lbs so around 45 kg. Throughout this process momentum is conserved so:
M1V1 + M2V2 = Σp
M1V1 + M2(-V2) = 0
M1V1= M2V2
So the total mass of the equipment and person is 115 kg and we’ll assume based on the video that the velocity of the person is 1.5 m/s up
115kg * 1.5 m/s = M2V2
Then we can assume that the velocity of the water is 5 m/s going downward.  Then we can solve for the mass of the water that is
115(1.5) = M2(5) M2 = 34.5 kg

Next we can use the power output of the Jet Ski to find the force needed to lift the flyboard and person to a velocity of 1.5 m/s. A jet ski has 200 horsepower.
200 hp (745.7 watts/ 1 hp) = 149140 watts
P = Fv
149140 watts = F (1.5 m/s)
F= 99, 400 N.
That is a lot of force needed to lift a person into the air! Thank goodness for technology, science fiction is becoming reality! Who knows what’s next!