ISRO Scientist or Engineer Mechanical Dec 2017

1 m

3 m

1.5 m

2 m

$$\frac{D}{2}\left[1 - \frac{\cos \alpha}{2}\right]$$

$$\frac{D}{2}\left[1 - \cos \alpha\right]$$

$$D \left(1 - \sin \alpha\right)$$

$$\frac{D}{2}\left[1 - \sin \alpha\right]$$

Dampingratio ($$\xi$$) is the ratioof thecritical damping to the actual damping

The damping can be obtained from the response of the system under forced vibration using logarithmic decrement method

For damped mechanical systems, the amplitude of vibration tends to become infinity when excitation frequency ($$\omega$$) reaches the system’s natural frequency ($$\omega_n$$)

Amplitude ratio and transmissibility of a vibration isolator is unity when the frequency of exciting force is $$\sqrt{2}$$ times the natural frequency

50 J/s

25 kJ/s

20 kJ/s

30 J/s

$$\frac{\pi}{2}$$

$$\frac{\pi}{4}$$

$$\frac{\pi^2}{2}$$

$$\frac{\pi^2}{4}$$

Pearlite

Cementite

Ferrite

Pearlite and Cementite

The beam section has a uniform shearstress, $$\frac{F}{bd}$$

Maximum shearstress in section and maximum bending stress in beam is equal when $$L = \frac{d}{2}$$

For $$L > \frac{d}{2}$$, bending stress decides the failure stress.

Bending stress developed in the beam is independent of ‘b’

7200 kW

5600 kW

2070 kW

4140 kW

In Carnot cycle, expansion of vapour occurs without change in entropy

In Rankine cycle, transformation of liquid water in steam generator occurs at constant temperature

In Carnotcycle, heating of vapor occurs at constant volume

In Rankinecycle, entropy of vapor increases during its expansion in steam turbine

Extrusion

Bending

Blanking

Coining