The following is in unstable equilibrium A. A uniform solid cone resting on a generator on a smooth horizontal plane B. A uniform solid cone resting on its base on a horizontal plane C. A solid cube resting on one edge D. A satellite encircling the earth

The correct answer is A. A uniform solid cone resting on a generator on a smooth horizontal plane.

A uniform solid cone resting on a generator on a smooth horizontal plane is in unstable equilibrium because if it is disturbed, it will tend to topple over. This is because the center of mass of the cone is not directly above the point of contact with the ground, so any disturbance will cause the cone to rotate about the point of contact.

A uniform solid cone resting on its base on a horizontal plane is in stable equilibrium because if it is disturbed, it will tend to return to its original position. This is because the center of mass of the cone is directly above the point of contact with the ground, so any disturbance will cause the cone to rotate about the point of contact in a way that brings the center of mass back to its original position.

A solid cube resting on one edge is in unstable equilibrium because if it is disturbed, it will tend to topple over. This is because the center of mass of the cube is not directly above the point of contact with the ground, so any disturbance will cause the cube to rotate about the point of contact.

A satellite encircling the earth is in stable equilibrium because if it is disturbed, it will tend to return to its original position. This is because the satellite is in orbit around the earth, and the force of gravity from the earth keeps the satellite in orbit. If the satellite is disturbed, it will move in a way that brings it back to its original position in orbit.