How powerful should the magnet be to repel against gravity?

[spidey]

i have two magnets and i want to repel one magnet against gravitational force upwards..so how powerful the magnet should be?i can calculate the gravitational force using Newton's law f=gm1m2/r2 where m1 is mass of Earth and m2 is mass of one magnet...so the magnetic force should be greater than this force ...help me...

 

[quark1005]

You require the force on the magnet to be equal to the force of gravity, as you said.

$$F = I \Delta l B sin \theta = \frac{Gm_{1}m_{2}}{r^{2}}$$

 

[tiny-tim]

i have two magnets and i want to repel one magnet against gravitational force upwards..so how powerful the magnet should be?i can calculate the gravitational force using Newton's law f=gm1m2/r2 where m1 is mass of Earth and m2 is mass of one magnet...so the magnetic force should be greater than this force ...help me...

Hi spidey!

Technically, it's Gm₁m₂/r²,

but we can write Gm₁/r² = g, the usual gravitational constant at the Earth's surface,

so f = Gm₁m₂/r² = m₂g.