The potential energy of a particle in a central field has the form U ( r ) = 1 r 2 - 1 r , where ' r ' is the distance from the centre of the field. The magnitude of the maximum attractive force in Newton is

Step-by-step solution

The relation between central force and potential energy is, F = - d U d r , given value of potential energy of a particle in a central field, U r = 1 r 2 - 1 r , it means, F = - d 1 r 2 - 1 r d r = - 2 r 3 + 1 r 2 , for maximum force, d - 2 r 3 + 1 r 2 d r = 0 ⇒ 3 r 4 - 2 r 3 = 0 ⇒ r = 3 2 , ⇒ F = 1 27