One end of a 2 m long steel rod (d = 3 cm) is rigidly attached to a wall so that the rod is perpendicular to the wall. the other end of the rod is welded to a second rod, which is 1 m long (d = 1.0 cm). the second rod is parallel to the wall and the floor. a vertical force of 50 n is applied to the end of the second rod. for both rods, the modulus of elasticity is 210 × 109 pa and the shear modulus is 79 × 109 pa.

as we know our atmosphere or air have different levels. every level has other gasses, and every gas has another permeability. when the light comes from lower permeability to higher permeability, it changes its direction. so that means that when the light comes from the moon to the earth, it changes it's direction many more times. it basically means that the shape of the light part of the moon is changed on the earth.

hope this ! this is not copied! search it up, it's free of plagiarism!