an electron is moving in a circular path of radius 1500 m perpendicular to a 2000 T magnetic fieldWhat is the tangential velocity of the electron?

The magnetic force e V B is (equals) the centripetal force m V^2/R. Therefore

e*B = m*V/R, which can be rewritten

V = e*B*R/m

The electren mass, m, must be in kg. e is is charge in Coulombs. B is in Tesla. V will be in m/s