**Deformation of a Block of Steel under Tangential Force**

When a block of steel is loaded by a tangential force on its top surface while the bottom surface is held rigidly, the deformation of the block is due to a combination of shear and bending.

**Shear and Bending**

* Shear: Shear is a type of deformation in which parallel planes within an object slide past each other. When the tangential force is applied on the top surface of the steel block, it creates shear stresses within the material. These shear stresses cause the layers of the block to slide or deform relative to each other.

* Bending: Bending is a type of deformation in which the material undergoes both compression and tension along its cross-section. When the tangential force is applied on the top surface of the steel block, it creates bending moments within the material. These bending moments cause the block to bend or deform, resulting in compression on one side and tension on the other side.

**Explanation**

When the tangential force is applied on the top surface of the steel block, it creates shear stresses and bending moments within the material. These stresses and moments are distributed across the cross-section of the block. The deformation of the block is a result of the combined effect of shear and bending.

The shear stresses cause the layers of the block to slide or deform relative to each other, resulting in shear deformation. This is particularly evident in the material near the top surface where the force is applied.

Simultaneously, the bending moments cause the block to bend or deform, resulting in compression on one side and tension on the other side. This bending deformation is more prominent in the middle and bottom regions of the block, away from the top surface.

Therefore, the deformation of the block under the tangential force is a combination of shear and bending. The shear deformation occurs near the top surface, while the bending deformation occurs throughout the block.

**Conclusion**

In summary, when a block of steel is loaded by a tangential force on its top surface while the bottom surface is held rigidly, the deformation of the block is due to a combination of shear and bending. The shear deformation occurs near the top surface, while the bending deformation occurs throughout the block.

As you can compare steel block to the any ( notebook or book) and hold it tightly from bottom apply tangential force on its top the only deformation comes by only shear by the angle of phi/2. shear which means that one particle slide over the next particle. and the angle which is phi/2 known shear strain..