A long solenoid with open ends is located along a constant magnetic field with an induction of B = 2 T. The number of turns per unit length of the solenoid n = 1000 m−1 How fast did a long metal projectile with a radius of r = 9 cm fly through this solenoid, if the maximum voltage that appeared at the ends of the solenoid is V = 100 kV? Ignore the metal resistance of the projectile.