To overcome a friction, certain amount of input force is needed, and actual mechanical advantage is difficult to be calculated thus, ideal mechanical advantage or IMA is calculated by taking ratio of input distance and output distance. It is mathematically represented as:
![IMA=(d_(i))/(d_(o))](https://img.qammunity.org/2019/formulas/chemistry/middle-school/x7h5dycuqlm2l6pk9e34xujtrjs8mc1k1p.png)
Here,
is input distance and
is output distance.
In the problem, input distance is 8 m and output distance is 2 m thus,
![IMA=(d_(i))/(d_(o))=(8 m)/(2 m)=4](https://img.qammunity.org/2019/formulas/chemistry/middle-school/6gn6mdpoq35ppwzt7djgh12ir76x7kvcd1.png)
Therefore, ideal mechanical advantage or IMA is 4.