A viaduct is being re-levelled by using a jackscrew with a pitch of 5mm. The mass of the top slab of the viaduct is 20 tonnes (20000kg) and its length is 40m. The lever arm used to turn the jackscrew is 60 cm long.

Calculate the effort force to be applied to the end of the lever arm of the jackscrew in order to lift the end of the top slab of the viaduct.