a uniform ring of mass m is lying at a distance of 1.73a fram a centre af a sphere M .the radius of both is a.what is the gravitational force exerted? i found gravitational field of ring and muliplied with mass of sphere to get the force. i got the answer.but if we find field ofsphere and muliplied with the mass of ring why the ans is different ?plz help me

dear charitha,

the ans in both the cases will be same, u wouild have done some mistake. if u cn post your calulation,u can seek tthe more help.

u hav askd whts the gravitational force....!!!!
but dude force on wic object...?????

your concept is correct , but this can be applied if the sphere is a point object wrt ring ...

size of sphere should be very very small wrt ring ...

now see if u are multiplying field of ring with mass of sphere then at which point u are considering the whole mass???? ...

field is  inversly proportional to distance of point so at different points on sphere field  will  be different ...

this question  is based on integration ....