InterviewSolution
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Two heavy spheres each of mass 100 kg and radius 0.10 m are placed 0.10 m apart on a horizontal table. What is the gravitational force and potential at the mid-point of the line joining the centres of the spheres? Is an object placed at that point in equilibrium? If so, is the equilibrium stable or unstable? |
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Answer» Here G = 6.67 x 10-11 Nm2 kg-2 M = 100 kg; R = 0.1 m Distance between two spheres, d = 1.0 m Suppose that the distance of either sphere from the mid-point of the line joining their centre is r. Then, r = d/2 = 0.5 m The gravitational field at the mid-point due to two spheres will be equal and opposite. Hence, the resultant gravitational field at the mid-point = 0 The gravitational potential at the mid-point = (-GM/r) x 2 = (-)6.67 x 10-11 x 100 x 2/0.5 = -2.668 x 10-8 J kg-1 As the net force on the body placed at midpoint zero, so the body is in equilibrium. If the body is displaced a little towards either mass body from its equilibrium position, it will not return back to its, initial position of equilibrium. Hence, the equilibrium attained is unstable. |
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