Ellen needs to move a heavy box across the floor and then place it on a shelf that is four feet above the floor. Which use of machines would most likely require the least amount of force in order to get the box on the shelf?

Rolling the box on a cart reduces friction, and an inclined plane lets Ellen raise it gradually rather than lifting it straight up. Using both together requires less force than sliding the box up the ramp or using a pulley that only changes the direction of the lifting force. So rolling it up an inclined plane on a cart is the best choice.

AI-written and checked against the verified answer.