3. an 8-inch diameter steel shaft is force fit into a cast iron disk with a 20-inch outside diameter. the maximum tangential stress in the disk is 5000 psi. if esteel = 30x106 psi and ecast iron = 15x106 psi, with poisson’s ratio  for both materials equals to 0.3, (a) determine the contact pressure required between the shaft and the disk (a: p  3621 psi ). (b) determine the decrease in the radius of the shaft (a: ds = 0.00034 inch). (c) determine the required diametral interference (a: 2 = 004 in. (hint: a change in the shaft radius or diameter can be obtained through the displacement in the shaft)

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.

If a particle moves along a path such that r : (3 sin t) m and ? : 2t rad, where t is in seconds. what is the particle's acceleration in m/s in 4 seconds? a)- 16.43 b)- 16.29 c)- 15.21 d)- 13.79

Give heat transfer applications for the following, (i) gas turbines (propulsion) ) gas turbines (power generation). (iii) steam turbines. (iv) combined heat and power (chp). (v) automotive engines