A bucket is swung in a vertical, circular path as shown.
The bucket is half filled with water and swung. The water stays in the bucket, even
at the top of the circular path, as long as the speed of the bucket exceeds a certain value.
Explain why.
A centripetal / unbalanced force is needed (because the water is moving in a
circular path)
Max 2
At the highest point the (unbalanced) force is weight of water plus reaction from
bucket
Idea that the minimum force needed (towards the centre of the circle) is the
weight of the water
[Credit may be given for a diagram with appropriate annotations]