Tech Monthly readers' photography project: forces

Wind Power! 'Kite surfers doing what they do!' Photograph: Paul McCarthy/GuardianWitness

The dramatic effect of force: 'Following a 'gully raker' wind gust this ancient tree was no match for the force of the wind'. Photograph: Matt Eliason/GuardianWitness

Wave Power: 'Can we harness it?' Photograph: TimmRanson/GuardianWitness

Graze anatomy: 'Tethered goat by the roadside in Western Crete'. Photograph: richardderwent/GuardianWitness

Defying the forces of gravity: 'Ropes and tractors pull these fishing boats clear of high tides at North Landing, Flamborough. Taken with my Nikon D7000 18-55mm lens'. Photograph: ID195271/GuardianWitness

Surface Tension: 'Surface tension is a property of the surface of a fluid, caused by cohesive forces between liquid molecules, allowing it to resist an external force (the water and the water strider)'. Photograph: BlakGard/GuardianWitness

Under the Trampoline: 'My daughter caught mid-flip, taken from under the trampoline. This is one of my favourite shots and was taken with a 1980's Olympus XA2 point and shoot, three zone film camera - a great piece of technology and design!' Photograph: filmloverjaxs/GuardianWitness

A slow moving force. Cuba - March 2014: 'Shot on a Nikon J1 through the windscreen of a moving minibus en route from the town of Trinidad to Holguin. This is not an unusual mode of transport in a country of many surprises'. Photograph: ID0770848/GuardianWitness

Brute force.... 'Hauling thousands of tons of freight across America daily by sheer, elegant, brute force. P.s. I have been looking for a nun to photograph for this assignment for a "force of habit" image but there never seems to be a nun around when you need one....' Photograph: fourthplinth/GuardianWitness

A human centrifuge on Hampstead Heath: 'hopefully the two empty seats were empty from the start'. Photograph: Simon Mackie/GuardianWitness