A round solid bar having a groove of 0.1-in deep with a 0.1-in radius machined into it. The material of the bar is AISI 1020 cold drawn steel, its diameter is 2.54 cm, and it is exposed to a
purely reversing torque of 1800 lbf. in. For the S-N curve of such material, take f = 0.9.
(a) Estimate the number of cycles to failure.
(b) If the bar is also placed in a 750◦F environment, estimate the number of cycles to failure.

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.

Afull journal bearing has a journal diameter of 27 mm, with a unilateral tolerance of -0.028 mm. the bushing bore has a diameter of 27.028 mm and a unilateral tolerance of 0.04 mm. the l/d ratio is 0.5. the load is 1.3 kn and the journal runs at 1200 rev/min. if the average viscosity is 50 mpa-s, find the minimum film thickness, the power loss, and the side flow for the minimum clearance assembly.

The thermal expansion or contraction of a given metal is a function of the f a)-density b)-initial temperature c)- temperature difference d)- linear coefficient of thermal expansion e)- final temperature f)- original length