An engine of mass 150kg is supported on four springs, each of stiffness 25 kn/m. due to the engine not being correctly balanced, when it runs at 15 rev/s a periodic force with a maximum value of 300 n acts on the system. what will be the maximum value of the force on the foundations on which the springs rest due to the engine running if it can be assumed that the engine only vibrates in the vertical direction?

Awall of 0.5m thickness is to be constructed from a material which has average thermal conductivity of 1.4 w/mk. the wall is to be insulated with a material having an average thermal conductivity of 0.35 w/mk so that heat loss per square meter shall not exceed 1450 w. assume inner wall surface temperature of 1200°c and outer surface temperature of the insulation to be 15°c. calculate the thickness of insulation required.