Final answer:
Lever systems provide a mechanical advantage by multiplying the force applied to overcome resistance. The longer the lever, the greater the force that can be exerted. Pulleys can also provide a mechanical advantage by multiplying the force applied.
Step-by-step explanation:
Lever systems provide a mechanical advantage by multiplying the force applied to overcome resistance. When the force applied, ma, is greater than the resistance force, ma, the lever system is able to lift larger loads with less effort. For example, in a nail puller, the longer the handle, the greater the force that can be exerted to pull out the nail.
The same concept applies to other types of levers, such as a wheelbarrow and a shovel. In a wheelbarrow, the load is between the pivot and the applied force, while in a shovel, the input force is between the pivot and the load. However, the mechanical advantage in a shovel is less than one because the input lever arm is shorter than the output lever arm.
Pulleys can also provide a mechanical advantage. Combinations of pulleys, when friction-free, can multiply the force applied. The mechanical advantage is approximately equal to the number of cables pulling directly upward on the system.