Question

find the force of attraction between wire and point mass ?gravitation chapter

Answer 1

Explanation:

The force on an individual charge moving at the drift velocity vd is given by F = qvdB sin θ. Taking B to be uniform over a length of wire l and zero elsewhere, the total magnetic force on the wire is then F = (qvdB sin θ)(N), where N is the number of charge carriers in the section of wire of length l. 

Answer 2

the universal law of gravitation states that

the force of attraction is directly proportional to the product of their mass and inversely proportional to the square of distance between them including their centre

(1) F ∝ M × m

(2) F ∝1/d^2

combining equation (1) and (2) , we get

F ∝ G(M × m)/d^2