A special C-clamp uses a 0.75-in.-diameter Acme thread and a collar of 1-in. effective mean diameter. The collar is attached rigidly to the top end of the externally threaded member. Determine the force required at the end of the 6-in. handle to develop at 300-lb clamping force. The friction coefficient in the thread is 0.2 and in the collar is 0.15. what is efficiency of the power screw

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.