All machines make work easier, but they don’t increase the amount of work that is done. You can never get more work out of a machine than you put into it. In fact, a machine always does less work on an object than the user does on the machine. That’s because a machine must use some of the work put into it to overcome friction. Friction is the force that opposes motion between any surfaces that are touching. All machines involve motion, so they all have friction. How much work is needed to overcome friction in a machine depends on the machine’s efficiency.
Andrew just moved into his new apartment but realized he made a mistake. He loaded a box too heavy for him to lift. He decides to try to push the mox into his house from the back of his building which has a very rough path and struggles to get the box in the house.
Given the pavement in front of Andrews apartment is much smoother would it be easier or harder to push the box inside?