how much does a jet ski weigh
Airplane? What airplane? My paper airplane wings weigh less than 8 grams.
Most people are surprised how much airplanes weigh, and engines too. Reciprocating engines typically weigh 1 pound per HP. Big jet engines weigh 0.2 pounds per HP or so and they typically weigh from one ton to several tons. Here a simulator for designing your own engine: http://www.grc.nasa.gov/WWW/K-12/airplane/ngnsim.htm
Stand on a scale. Figure out how much you weigh. Then pick up the airplane and stand on the scale. Subtract how much you originally weighed, and that is the weight of the airplane.
lots lots
a bunch.
Jet propulsion improved airplane flights. Before that piston engines were used. They were much slower compared to the jet engine.
Fueling a jet is so much money.
12 pounds
a bunch
A paper airplane? A 747? Cessna?
It depends on what kind of jet or commercial airplane it is.