answer which casting design will have better quality from the sand mold casting and explain the reason for your answer wit one sentence

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.

Acircular pipe of 30mm outside diameter is placed in an airstream at 30 c and latm pressure. the air moves in cross flow over the pipe at 20 m/s, while the outer surface of the pipe is maintained at 110 c. what is the drag force exerted on the pipe per unit length? what is the rate of heat transfer from the pipe per unit length?

Around steel bar, made from material with a yield stress of 750mpa, is loaded so that it has stresses co locations of maximum normal stress and maximum shear stress. use maximum shear stress and maximum distortion energy theories to calculate the safety factors for initial yielding failures.