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19 cm ಎತ್ತರದ ಲಂಬ ವೃತ್ತಾಕಾರದ ಶಂಕುವಿನ ಆಕಾರದ ಫ್ಲಾಸ್ಕ್ ನೀರಿನಿಂದ ತುಂಬಿದೆ. ನೀರನ್ನು ವೃತ್ತಾಕಾರದ ಶಂಕುವಿನ ಆಧಾರದ ತ್ರಿಜ್ಯದ ಮೂರನೇ ಒಂದು ಭಾಗದಷ್ಟು ತ್ರಿಜ್ಯವನ್ನು ಹೊಂದಿರುವ ಲಂಬ ವೃತ್ತಾಕಾರದ ಸಿಲಿಂಡರಾಕಾರದ ಫ್ಲಾಸ್ಕ್ಗೆ ಸುರಿಯಲಾಗುತ್ತದೆ. ಹಾಗಾದರೆ, ಸಿಲಿಂಡರಾಕಾರದ ಫ್ಲಾಸ್ಕ್ನಲ್ಲಿನ ನೀರಿನ ಎತ್ತರ ಎಷ್ಟು?
83 cm
57 cm
53 cm
73 cm
57 cm
Since Vcone=Vcyl, equate 31πrc2(19)=π(3rc)2hy. The π and rc2 terms cancel, leaving hy=19×3=57 cm.
Cone height hc = 19 cm. Cylinder radius ry = (1/3) * Cone radius rc. The cone is filled with water.
Vcone=31πrc2hc and Vcyl=πry2hy
Since Vcone=Vcyl, equate 31πrc2(19)=π(3rc)2hy. The π and rc2 terms cancel, leaving hy=19×3=57 cm.
Students often forget to square the ratio 1/3 when substituting the radius, leading to hy=19×3=57 rather than 19×32=171.
Equating Volumes
Since the water volume is constant, the volume of the cone equals the volume of the cylinder: Vcone=Vcyl
31πrc2hc=πry2hy
Substitute Given Values
Substitute hc=19 and ry=3rc into the equation: 31πrc2(19)=π(3rc)2hy
319rc2=9rc2hy
Solve for Height
Cancel rc2 from both sides and solve for hy: hy=319×9=19×3=57
hy=57 cm
B is correct because the conservation of volume formula yields a height of 57 cm for the cylinder.
This concept is a precursor to fluid dynamics and surface area problems often appearing in mechanical engineering aptitude sections.