The US Navy is developing a railgun that uses magnetic field repulsion. The railgun can propel a 981 N projectile at seven times the speed of sound. How much energy is stored in this magnetic field? Assume a complete conversion of energy and a speed of sound of 340 m/s.

Ahole in the ground in the shape of an inverted cone is 14 meters deep and has radius at the top of 11 meters. the cone is filled to the top with sawdust. the density of the sawdust depends upon the depth, x, following the formula ρ ( x ) = 2.5 + 1.2 e − 0.7 x kg/m3. find the total mass of sawdust in the conical hole.