If you pull 100lbs on a 3:1 system, what will be the output force?

In a simple pulley system, the mechanical advantage determines how much the input force can amplify the output force. A 3:1 pulley system means that for every three units of distance you pull the rope, the load is lifted one unit of distance. This system allows you to lift heavier loads with less effort.

When you apply a force of 100 lbs to a 3:1 system, the mechanical advantage indicates that the output force can be calculated by multiplying the input force by the ratio of the system. Thus, for a 3:1 system:

Output Force = Input Force × Mechanical Advantage

In this case, the calculation for the output force would be:

Output Force = 100 lbs × 3 = 300 lbs.

This is why the output force in a 3:1 system when you pull 100 lbs is indeed 300 lbs. The system effectively triples the force you are exerting, allowing you to lift heavier loads with the same amount of input effort.