Consider the following statements: X. Two-dimensional stresses applied to a thin plater in its own plane represent the plane stress condition. Y. Normal and shear stresses may occur simultaneously on a plane. Z. Under plane stress condition, the strain in the direction perpendicular to the plane is zero. Which of the above statements are correct?

Correct Answer: 1 and 3
Under plane stress condition, the strain in the direction perpendicular to the plane is not zero. It has been found experimentally that when a body is stressed within the elastic limit, the lateral strain bears a constant ratio to the linear strain.