Why would a doctor suggest converging lenses to correct a patient’s vision?

To correct the problem of farsightedness

Explanation:

In the problem of  farsightedness, an object which is far away look clear while an object which is near to eye lens it looks blurr as the image of the object is formed behind the retina.

In order to converge all the light rays passing through an eye lens at its retina a convex lens is used. A convex lens enables  the meeting of rays at the retina and thus they need not to travel beyond retina to meet at some point.

explanation:

the universal gravitation equation. since the gravitational force is directly proportional to the mass of both interacting objects, more massive objects will attract each other with a greater gravitational force. if the mass of one of the objects is doubled, then the force of gravity between them is doubled.