Question
Question: The difference between pressure and stress is: (A) pressure and stress have different units (B) ...
The difference between pressure and stress is:
(A) pressure and stress have different units
(B) pressure and stress have different dimensions
(C) force cannot be determined using stress, but in pressure it can be done
(D) pressure is applied to a body, while stress is induced
Solution
Hint
Both the pressure and stress have the same formula force divided by area, and having the same SI unit and having the same dimensional unit. But both the pressure and stress functions are different. By knowing the function of the pressure and stress the solution can be determined.
Complete step by step answer
Pressure is defined as the amount of force exerted per unit area. And pressure is the force which applies perpendicular to the surface of an object per unit area. Pressure is always acting normal to the surface. Magnitude of the pressure at a point in all the directions will remain the same. And the pressure can be measured by using a measuring device like a pressure gauge. Pressure is applied to the body. And the pressure is used in liquids also. Pressure is denoted as (P).
Stress is defined as the amount of force induced by unit area, experienced by a material. Stress represents the intensity of internal resisting forces developed at a point. Stress may also act either normal or parallel to the surface. The magnitude of the stress at any point in all the directions are not equal. The stress cannot be measured directly by using any measuring instruments. Stress is often seen in solid particles only. Stress is denoted as (σ).
Hence, the option (D) is the correct answer.
Note
Pressure always tries to compress the surface on which it is applied. But the stress can be tensile or compressive depending on the load type. Pressure is a positive unit but stress can be either positive or negative, the negative is because of internal resisting force.