Material Science

Step 1: Understand the behavior of steel under stress.
In the stress-strain curve for structural steel, necking occurs after the material has yielded. The material begins to deform plastically after the yield point and necking starts before the ultimate strength. Step 2: Conclusion.
Necking is a localized reduction in the cross-sectional area of the material and begins after the yield point, not at the ultimate strength. Final Answer:

Step 1: Analyze the given ratio.
The ratio is a function of temperature ratio , and it typically corresponds to a specific heat or thermal conductivity ratio. Step 2: Conclusion.
This ratio is given by , which is derived from the laws of thermodynamics. Final Answer:

Step 1: Understand the sequence of observations in a tensile test.
- Proportionality limit is the first point where stress and strain are directly proportional (Hooke’s Law).
- Elastic limit is the point beyond which the material no longer behaves elastically.
- Yield point is where permanent deformation starts.
- Fracture point is where the material ultimately breaks.
Step 2: Conclusion The correct sequence of observation after loading is (A), (B), (C), (D). Final Answer:

Concept: In robotics, joints are classified based on the type of motion they allow. Translatory joints permit linear motion, unlike rotational joints.
Step 1: Understanding translatory motion.
A translatory (linear) joint allows movement along a straight line without rotation.
Step 2: Identifying the sliding joint.
The Prismatic Joint allows linear sliding motion between two links, similar to a piston moving inside a cylinder. Hence, it is also called a sliding joint.
Step 3: Eliminating incorrect options.

• Revolute Joint allows rotational motion.
• Cylindrical Joint allows both rotation and translation.
• Spherical Joint allows multi-axis rotation.

Conclusion:
Thus, the correct answer is Prismatic Joint.