When a container of water is placed on a laboratory scale, the scale reads 120 g. Now a 20-g piece of copper (of density 8.9 g/cm 3) is suspended from a thread and lowered into the water, not touching the bottom of the container. What will the scale now read?

A. 122 g B. 140 g C. 120 g D. 112 g E. 138 g

Question

Physics

Ashleigh

27 September, 07:54

When a container of water is placed on a laboratory scale, the scale reads 120 g. Now a 20-g piece of copper (of density 8.9 g/cm 3) is suspended from a thread and lowered into the water, not touching the bottom of the container. What will the scale now read?

A. 122 g B. 140 g C. 120 g D. 112 g E. 138 g

+2

Answers (1)

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Case Whitney · Answer 1

A) 122 g

Explanation:

volume of water displaced

=/frac{20}{8.9}//

= 2.247 cc

weight of water displaced = 2.247 g wt

upthrust = 2.247 g wt

Reaction of upthrust acting in downward direction = 2.247 g wt

reading of scale = 120 + 2.247 = 122.247 g