Question

If a pulley system with an actual mechanical advantage of 3,000,000 is used in lifting a 3,000 lb. car, what effort would be needed to move the car?

Answer 1

Mechanical advantage is the ratio of the force (or effort) applied *to* a machine compared to the force which is output *by* the machine.
Considering the pully system with a Mechanical Advantage of 3,000,000, this means that a force applied to the pully system will result in a force output which is 3,000,000 times greater than the force input.

So, while it would take 3000 pounds of force to lift the 3000 pound car without the pully system, it will take 3,000,000 times *less* effort to lift the car with the pully system. Now, what is 3000/3,000,000? That is the amount of effort in pounds it will take