A washing machine of mass m = 80 kg has an unbalance that creates a harmonic force of magnitude F. A spring- damper system is designed to minimize the force transmitted to the base of the machine. The spring is having
stiffness coefficient k 350000 N/m. Calculate the required damping coefficient c, [N. s/m), so that only 15%
of the generated force F, is transmitted to the ground when the machine is running at 4500 rpm.
01305.74
06862.08
03528.28
05556.34
[N. s/m]

Determine the time of the day and month of the year at which the peak sensible cooling load occurs for a top floor, north-eastern corner room of an office building in durban for the following conditions: floor area: 8 x 8 x 3 m east and north walls: 115 mm face brick (outside), 20 mm air space, 115 mm ordinary brick (inside) with 15 mm plaster roof construction: suspended plasterboard ceiling, 450 mm air space, 150 mm concrete, 75mm screed, waterproofing no heat transfer across other surfaces window area 3x 1,5 m high in north wall only. ordinary glass with venetian blinds. lights and occupants : from 07: 00 to 18: 00 average light density: 25 w/m2 number of occupants : 5 seated, light office work room temperature 24°c