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Re: [Phys-L] Nice question on buoyance and balance

To show that the LHS load for the floating ping pong ball= the LHS load for the tethered and submerged ping ball ball ==>

1) The downward force (due to the floating ping pong ball) on the beaker bottom, in the floating case = mg (the weight of the ping pong ball).

2) In the tethered case the downward force on the ball is mg + T - Fb = 0

3) The downward force on the beaker bottom = Fb - T

4) Using 2) in 3) the downward force on the beaker bottom in the tethered case = mg

5) Observe that 1) = 4) , QED.


ie, tethering the previously floating ball to the floor does not affect the scale reading.

Bob Sciamanda
Physics, Edinboro Univ of PA (Em)
treborsci@verizon.net
http://sciamanda.com