SOLUTION: The ball of a float valve has a diameter of 4 in., and the thickness of the metal is 0.05 in. How much does it weigh if it is made of copper? (Copper weighs 556 lb. per cu. ft.)
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-> SOLUTION: The ball of a float valve has a diameter of 4 in., and the thickness of the metal is 0.05 in. How much does it weigh if it is made of copper? (Copper weighs 556 lb. per cu. ft.)
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Question 1181645: The ball of a float valve has a diameter of 4 in., and the thickness of the metal is 0.05 in. How much does it weigh if it is made of copper? (Copper weighs 556 lb. per cu. ft.) Found 2 solutions by mananth, ikleyn:Answer by mananth(16946) (Show Source):
You can put this solution on YOUR website! Outer volume - inner volume = volume of copper.
Volume of copper * density of copper = weight of copper
outer radius = 2 "
inner radius = 2- 0.05 = 1.95 "
Volume of copper= (4/3)*pi * (2-1.95)^3
V= 0.000523 in^3
556 lb/ft^3= 5.15 ounce/in^3
Weight of copper = 0.000523* 5.15
= 0.0027 ounces
If to combine all incorrect solutions/answers by @mananth at this forum,
it would comprise an entire book showing all possible and typical errors
and teaching on how Math problems should not be solved at any circumstances !
See my correct solution below.
Outer volume - inner volume = volume of copper.
Volume of copper * density of copper = weight of copper
outer radius = R = 2 inches
inner radius = r = 2- 0.05 = 1.95 inches.
Volume of copper = - =
V= 2.449 in^3
556 lb/ft^3 = 0.322 lb/in^3
Weight of copper = 2.449 * 0.322 = 0.789 pounds. ANSWER
Notice that the correct answer is about 5000 times the incorrect answer by @mananth ( ! ) ( ! ! ) ( ! ! ! )
