When you swing a bucket of water up and down in a vertical circle you
can keep the water in the bucket if you keep the velocity high enough.
 If you let the bucket slow down you get wet.  The critical velocity
is the slowest velocity necessary to keep the water in the bucket and
not on you.  What is the critical velocity for you if the formula is
velocity = square root of(rg) where the radius of your arm swing including the
bucket is r and g is the acceleration of gravity? Hint: You must
measure or estimate the length from your shoulder to the center of the
bucket for the radius.

You've been given the formula: v = SQRT(rg) g ~ 9.8 m/s^2, which makes
it v = SQRT(r9.8). The only unknown on the right side of the equation
is r, the length of your arm. So how long is your arm?

...Your arm's length in meters, that is. If you're working in feet,
inches, or whatever, then you need to find your arm's length in those
units, and change the 9.8 to its equivalent in the other units. For
feet, 9.8 is about 32.17 ft/s^2.

Does the question make any sense? You've got the ultimate formula for
V. Isn't it just measure your arm and the length of the bucket
including the handle, and do a simple math? BTW, G=9.8m/(s^2).