In a problem, it is given that a mass of 10.2 Kg is resting on a cube made out of a particular material. Assuming that the x-axis is vertically upwards, what is the stress on the cube. (We can say that the cube is lying on a surface, and the positive x-axis is pointing upwards.)
I am confused about two things:
- What is the sign convention for denoting the stress. Would the stress be negative or positive (I think negative, as it is pointing in the negative x direction).
- Do we also consider the stress due to normal reaction from the surface.