# Latest Mechanical Updates | Aptitude Questions For Mechanical Engineers

Contents

### What is the material composition in IBR tubes? Latest Mechanical Updates

Carbon max………………… 0.10%

Manganese max……………. 0.60%

Nickel max…………………. 0.25%

Sulphur max………………… 0.050%

Phosphorus max…………….. 0.050%

### What is the difference between P11 & P22 pipes?

P11 is the chromium molybdenum composition that is 1% of chromium and 1/4% of molybdenum

P12 is the chromium molybdenum composition that is 1% of chromium and 2% of molybdenum

### 1st Law of Thermodynamics | Latest Mechanical Updates

a. Heat and Mechanical Work are mutually convertible.

b. Energy can neither be created nor destroyed, but it can be transferred from one form to another form.

### The Difference between Unilateral tolerance and Bilateral tolerance

A unilateral tolerance is a tolerance in which variation is permitted only in one direction from the specified direction. e.g., 1800 +0.000/-0.060

Bilateral tolerance is tolerance in which variation is permitted in both directions from the specified direction. e.g., 1800 +0.060/-0.060

Read More:   Mechanical Objective Questions | Mechanical Objective Type

### Why do we need two angles of projection ( 1st angle and 3rd angle)? Can’t we standardize to one?

Generally, the first-angle projection is followed in India and the third-angle projection is used in European countries. In 1st and 3rd angle projections, there is no overlapping of principal planes while drawing side and top views. But in the 2nd and 4th angle projections, the principal planes are overlapped while drawing top and side views. It results in confusion in the drawing. For this reason, 1st and 3rd angle projections are commonly used.

### During which of the following processes does heat rejection take place in Carnot vapour cycles | Latest Mechanical Updates

1. Constant volume
2. Constant pressure
3. Constant temperature
4. Constant entropy

Constant Temperature

### What is the difference between corrective actions and preventive actions?

Corrective actions are taken on discrepancies noticed during the inspection of products/documents/processes, whereas preventive actions are taken to eliminate the possibility of discrepancies in the future.

### What is a shaft coupling and its types? The Latest Mechanical Updates

It is used to join two shafts for transmitting motion from one shaft to another shaft, it may be either flexible or rigid type.

Rigid coupling; (Muff coupling, Flange coupling, Marine coupling, Oldham”s coupling, Flexible coupling, Flexible bush pin coupling)

Oldham’s Coupling is used when the axis of the shaft are not aligned

Other types are:

loveys joy coupling

Spider coupling

Tyre coupling

Pin and bush coupling

Fluid coupling

Vulcan coupling

Flexible coupling

Universal coupling

Articulate joints

### What is meant by One ton Air conditioner, how fast it cools a room.

1-ton refrigeration means 210 kJ/min extracts heat from the system.

### Boyle’s law

Boyle’s law describes the inversely proportional relationship between the absolute pressure and volume of a gas.

### When temperature increases the frequency of the tuning fork

a. Increases
b. Decreases
c. Remain the same
d. Increases or decreases depending on the material

B. Decreases

Reason:
During the idling period, no petrol is drawn from the carburetor and the float inside the float chamber floats exerting pressure on the fluid as a result of which the inflow of the fuel to carburetor is stopped.

### The exact analysis of viscous flow problems can be made by

a. Euler’s equation
b. Hagen poiseuille’s equation
c. Continuity equation
d. Navier-stroke’s equation