Arocket with a mass of 2.0 ã 106 kg is designed to take off from the surface of the earth by burning fuel and ejecting it with an exhaust speed of 3500 m/s. what is the minimum rate at which the fuel should be consumed in order to attain liftoff?

thrust force getting from the burning of mass should balance the weight of the rocket

here thrust force is given as

now by force balance we can say

now plug in all values in this

so rate of mass burning per second will be 5600 kg per second in order to lift up the rocket

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