Q2. The shafts are designed on the basis of rigidity and stiffness.
- Correct
- Incorrect
Answer A. Correct
Solution:
The shafts are designed on the basis of strength or rigidity or both. The goal of a strength-based design is to ensure that stress at any point on the shaft does not exceed the yield stress of the material. The goal of rigidity-based design is to keep the shaft's maximum deflection (due to bending) and maximum twist (due to torsion) within acceptable bounds. In some circumstances, rigidity is also significant. For example, if the shaft is deflected, the position of a gear mounted on the shaft may change, and if this value exceeds some permissible limit, it may cause excessive dynamic loads and noise in the gears.
Q3. Work done in a free expansion process is.
- Positive
- Negative
- Zero
- None of the above
Answer: C. Zero
Solution:
Work done in a free expansion process is zero. No external pressure acts on the gas during a free expansion, causing it to expand. The gas expands on its own when no external pressure is applied. The work done during free expansion is little or negligible because the external pressure is zero.
Q4. The friction experienced by a body in motion is known as
- Rolling Friction
- Dynamic friction
- Limiting Friction
- Static Friction
Answer - B. Dynamic Friction
Solution:
The friction experienced by a body in motion is known as dynamic friction. The body enters into motion when the force acting on it is greater than the limiting friction. Dynamic friction is the type of friction that now exists between the contact surfaces. The limiting static friction is always less than the dynamic friction.
Q5. Slip of a reciprocating pump is defined as the
- Difference of theoretical discharge and actual discharge.
- Ratio of actual discharge to theoretical discharge.
- Ratio of theoretical discharge to actual discharge.
- None
Answer: A. Difference of theoretical discharge and actual discharge.
Solution:
Slip of a reciprocating pump is defined as the difference of theoretical discharge and actual discharge.
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