4. A roof has a rise of 6 ft 5 in. and a run of 12 ft 8 in. To the nearest 1/4", find the length of the roof
rafters, as shown. Disregard any overhang?

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.

How to increase the thermal officiency of an ideal simple rankino cycle? among these methods, which one is the best and why?

What is a monomer? how do they form a ploymer from the view point of chemical bonding?