A heat pump (working in a thermodynamic cycle mode) is to be used to heat a house during the winter. The house is to be maintained at 294 K at all times. The house is estimated to be losing heat at a rate of 135,000 kJ/h when the outside temperature drops to 268 K. If the heat pump under these conditions has a coefficient of performance of 4, (a) Determine the power required to drive this heat pump (b) Determine the rate at which heat is absorbed from the cold outdoor air Repeat the questions assuming the heat pump works in a reversible mode. You need to calculate the coefficient of performance under these conditions.

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.

The higher the astm grain-size number, the coarser the grain is. a)-true b)-false

Shafts are machine elements that are used to a) carry axial loads b) direct shear loads c) transmit power d) rotate at constant speed e) none of the above circular and square shafts subjected to the same torque under the same circum behave a) the same way b) almost the same way