3.00x10^8 m/s to dermine how many kilometers a pulse from a lazer will travel in one hour

(3 x 10⁸ m/s) x (60 s/min) x (60 min/hr) =

(3 x 10⁸ x 60 x 60) (m-sec-min/sec-min-hr) =

(3 x 10⁸ x 3600) meters =

1.08 x 10¹² meters  or  1.08 billion kilometers

we need to know the time interval during which the force acts. impulse of force = momentum change

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it