<P> An elevator with a counterbalance approximates an ideal Atwood machine and thereby relieves the driving motor from the load of holding the elevator cab -- it has to overcome only weight difference and inertia of the two masses . The same principle is used for funicular railways with two connected railway cars on inclined tracks , and for the elevators on the Eiffel Tower which counterbalance each other . Ski lifts are another example , where the gondolas move on a closed ( continuous ) pulley system up and down the mountain . The ski lift is similar to the counter-weighted elevator , but with a constraining force provided by the cable in the vertical dimension thereby achieving work in both the horizontal and vertical dimensions . Boat lifts are another type of counter-weighted elevator system approximating an Atwood machine . </P>
what is a real world application of an atwood machine
An elevator with a counterbalance