Two identical heavy spheres of equal mass are placed on a smooth cup of radius 3 r where r is radius of each sphere.Then the ratio of reaction force between cup and any sphere to reaction force between two sphere is

Two metal spheres each of radius r are kept in contact with each other. If d is the density of the material of the sphere,then the gravitational force between those spheres is proportional to

Two identical spheres each of radius R are placed with their centres at a distance nR , where n is integer greater than 2 . The gravitational force between them will be proportional to

A solid sphere of mass m and radius R is placed over a plank of same mass m . There is sufficient friction between sphere and plank to prevent slipping. Force of friction between sphere and plank is

Two identical copper spheres of radius R are in contact with each other. If the gravitational attraction between them is F , find the relation between F and R .

Two identical spheres each of mass M and radius R are separated by a distance 3R. The force of attraction between them is proportional to

Two identical solid copper spheres of radius R placed in contact with each other. The gravitational attracton between them is proportional to

From a sphere of mass M and radius R, a smaller sphere of radius (R)/(2) is carved out such that the cavity made in the original sphere is between its centre and the periphery (see figure. ) for the configuration in the figure where the distance between the centre of the original sphere and the removed sphere is 3R, the gravitational force between the two sphere is : (##DSH_NTA_JEE_MN_PHY_C07_E01_012_Q01.png" width="80%">

A plank of mass M is placed over smooth inclined plane and sphere is also placed over the plank. Friction is sufficient between sphere and plank. If plank and sphere are released from rest, the frictional force on sphere is - .

Two identical copper spheres of radius R are in contact with each other. If the gravitational attraction between them is F, find the relation berween F and R.