Two identical beakers are filled with the same amount of water.A ball of mass m is placed in the first beaker so that it floats on the surface while a second identical ball is placed in the second beaker but tied with a string of negligible mass so that the ball is completely submerged.Each beaker is then placed on a scale.Which scale has a higher reading?
A)(a)
B)(b)
C)the same
D)depends on how far the ball is submerged in (b)
E)unable to tell

Question

Two identical beakers are filled with the same amount of water.A ball of mass m is placed in the first beaker so that it floats on the surface while a second identical ball is placed in the second beaker but tied with a string of negligible mass so that the ball is completely submerged.Each beaker is then placed on a scale.Which scale has a higher reading? 
A)(a) 
B)(b) 
C)the same 
D)depends on how far the ball is submerged in (b) 
E)unable to tell

Quizplus · Accepted Answer

The weight of the ball in the first beaker is equal to the weight of the water displaced by the ball, which is equal to the weight of the ball in the second beaker (since the two balls have the same volume and density). Therefore, the total weight of each beaker-ball system is the same, and hence the two scales will read the same. The depth to which the second ball is submerged does not affect the weight reading on the scale, as the weight of the water that the ball displaces is already accounted for in the weight reading.

Two Identical Beakers Are Filled with the Same Amount of Water.A