A rock of mass M,that has a density twice that of water,is suspended in water by a thin,massless cord.The tension in the cord is
A)2Mg
B)Mg
C)Mg/2
D)zero
E)impossible to determine from the information given.

Question

Quizplus · Accepted Answer

The buoyant force on the rock is equal to the weight of the water displaced, which is Mg/2. Therefore, the tension in the cord is the weight of the rock minus the buoyant force, which is Mg - Mg/2 = Mg/2.

A Rock of Mass M,that Has a Density Twice That