On a cold (−10◦C) winter day, a heat pump provides 20 kW to heat a house maintained at 20◦C and it has a COPHP of 4. How much power does the heat pump require? The next day, a storm brings the outside temperature to −15◦C, with the same COP and the same house heat transfer coefficient for the heat loss to the outside air. How much power does the heat pump require then?

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.

Fluids at rest possess no flow energy. a)- true b)- false

Afluid flows with a velocity field given by v=(x/t)i.. determine the local and convective accelerations when x=3 and t=1.