Why does water stay in the bucket if it is swung through a loop fast enough?

Water stays in the bucket for the same reasons that we stay in our seats when we do a loop on a rollercoaster. Another example is being driven round a roundabout and feeling a 'force' pushing you outwards away from the roundabout. 

The cause of this 'force' is known as inertia- which is given by Newton's First Law of Motion: objects will remain at rest or at constant velocity unless acted on by an external force. 

As we swing the bucket through the loop, the water experiences a downward force due to gravity, which is accelerating the bucket's contents down towards the ground. 

However, the water also has another force acting on it. The sides of the bucket push on the water and cause it to have another acceleration, tangential to the circle the bucket is being swung through. Therefore, at the top of the swing, the water feels a downward force towards the ground (due to gravity) and a sideways force perpendicular to the ground (due to the bucket walls). The resultant of these two forces is a diagonal force, accelerating the water down and along. Thus, the water falls diagonally, where it is caught by the bucket again as it moves through the circle and remains in the bucket!  

Answered by Bethany B. Physics tutor

7681 Views

See similar Physics A Level tutors

Related Physics A Level answers

All answers ▸

A cricketer throws a ball vertically upwards so that the ball leaves his hands at a speed of 25 m/s. Calculate the maximum height reached by the ball, the time taken to reach max. height, and the speed of the ball when it is at 50% max. height.


Two pendulums consist of a massless rigid rod of equal length attached to a small sphere of equal radius, with one sphere hollow for one pendulum and the other solid. Each pendulum undergoes damped SHM. Which pendulum has the largest time period?


A motorist traveling at 10m/s, was able to bring his car to rest in a distance of 10m. If he had been traveling at 30m/s, in what distance could he bring his cart to rest using the same breaking force?


Explain what is meant by specific latent heat of fusion


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo
Cookie Preferences