Some people claim that the spin of water in a sink (or bathtub ortoilet or whatever) is caused by the Coriolis effect and theEarthâs rotation. Suppose a drain is opened in the center of alarge tank with a flat, frictionless, bottom that is filled withwater initially at rest and located at 45oN. After some time t thetangential velocity 1 cm from the drain axis is observed to be 0.5cm/s.
(a) If only the Coriolis force was responsible for the observedswirl, what was the initial radial distance of the fluid ring thatwas observed at 1 cm radius at time t?
(b) Suppose that instead of being initially at rest, the water hada small, initial, clockwise swirl. At the initial radial distancefrom part (a) above, how large would the tangential velocity ofthis swirl have to have been in order to reverse the spin of thedrain vortex?
(c) Do you think you could easily detect the velocity in part (b)?What can you conclude about the popular claim?
Some people claim that the spin of water in a sink (or bathtub ortoilet or whatever) is caused by the Coriolis effect and theEarthâs rotation. Suppose a drain is opened in the center of alarge tank with a flat, frictionless, bottom that is filled withwater initially at rest and located at 45oN. After some time t thetangential velocity 1 cm from the drain axis is observed to be 0.5cm/s.
(a) If only the Coriolis force was responsible for the observedswirl, what was the initial radial distance of the fluid ring thatwas observed at 1 cm radius at time t?
(b) Suppose that instead of being initially at rest, the water hada small, initial, clockwise swirl. At the initial radial distancefrom part (a) above, how large would the tangential velocity ofthis swirl have to have been in order to reverse the spin of thedrain vortex?
(c) Do you think you could easily detect the velocity in part (b)?What can you conclude about the popular claim?
