Final answer:
The mechanical advantage of the lever is 3, calculated by dividing the length of the effort arm (9 m) by the length of the resistance arm (3 m).
Step-by-step explanation:
The mechanical advantage of a lever is defined as the ratio of the length of the effort arm to the length of the resistance arm. In the example given, the effort arm is 9 m long and the resistance arm is 3 m long. Using the formula for ideal mechanical advantage (IMA), which is IMA = length of the effort arm (Le) divided by the length of the resistance arm (Lr), the mechanical advantage is calculated as follows:
IMA = Le / Lr
IMA = 9 m / 3 m
IMA = 3
Therefore, the mechanical advantage of the lever is 3. This means that the lever multiplies the input force (the effort force) by a factor of 3.