Can a machine be useful even if its mechanical advantage is less than one explain and give an example?

Yes, a machine can still be useful even if its mechanical advantage is less than one. This can happen when the machine reduces the amount of force needed to perform a task, even though the output force is less than the input force. An example of this is a pulley system, where the force needed to lift an object is reduced by distributing the load over multiple ropes and pulleys.