Why can water stay in bucket if you spin it upside down, if you spin the bucket fast enough? what are some practical applications of this?

Water stay in the bucket if the bucket is spin upside down and fast because due to centripetal force.

Explanation:

When the bucket is at highest point in the circular motion then there will be three forces work centripetal force in upward direction ann normal and weight will work in downward direction.

By newton law,

centripetal force=weight + normal force.

If the water will stay in the bucket in upside direction then there will be normal force is positive which means the centripetal force is greater than weight.

And to increase the centripetal force velocity should be greater because it depends on velocity.

The practical application of centripetal force are discussed below:

(a) Turning of the car on a banked road or in circular track.

(b) Revolution of the earth around the sun.

cant without the picture! ?