Toricelli's Law Proof for Water Leaking from a Reservoir

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Toricelli's Law describes the rate of water leaking from a reservoir, stating that the rate of change of volume dV/dt is proportional to the square root of the height of the water y. The discussion involves proving that the height y satisfies the differential equation dy/dt = -1/200(sqrt(5y)) for a cylindrical reservoir with specific dimensions and a hole at the bottom. The volume of the cylinder is calculated as (5/4)π, while the area of the hole is determined to be approximately 0.00196 m². The user is seeking guidance on expressing the volume V(t) in terms of the height y(t) to proceed with the proof. Understanding these relationships is crucial for completing the proof of Toricelli's Law in this context.
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toricellis law ? proof ??

Homework Statement



Let y(t) and V(t) be the height (in m) and the volume of the water (m^3), respectively, in a resevoir at time t (in s). If the water leaks out through a hole of area a ( in m^2) at the bottom of the resevoir, Toricelli's Law states that dV/dt= -a(squareroot(2gy)) where g is the acceleration due to gravity.

Suppose that the resevoir is a cylinder of height 5m and radius 50cm and that the hole in the bottom is circular with radius 2.5cm. If we take g=10m/s^2, show that y satisfies dy/dt= -1/200(squareroot(5y))

Homework Equations





The Attempt at a Solution



Well i figured the volume of the cylinder is (5/4)pi and area of small circle is 0.00196m^2 i don't know what to do next ?? please help ..
 
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Express V(t) in terms of y(t).
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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