Answer:
For brittle material ,ultimate strength use to determine the factor of safety but on the other hand for ductile material yield strength use to determine the factor of safety.
Step-by-step explanation:
Factor of safety:
When materials are subjected to stress then we have to prevent it from a failure so we multiple stress by a factor and that factor is called factor of safety.
Factor of safety can be given as
![FOS=(Maximum\ strength)/(Applied\ stress)](https://img.qammunity.org/2020/formulas/engineering/college/r33652m6bpkxc4umcdk9m9dgl822mz46i9.png)
Factor of safety is not a fixed quantity is varies according to the situation.
For brittle material ,ultimate strength use to determine the factor of safety but on the other hand for ductile material yield strength use to determine the factor of safety.
We know that brittle material did not shows any yield point and gets break without showing a indication but ductile materials shows a yield point and gives indication before fracture.