Pulleys and block-and-tackles are often used to hoist objects into the upper levels of barns and garages. the supports that hold these contraptions come in various forms. let us model the illustrated orange support as a planar truss with horizontal member ac that is subjected to the vertical tension load t . given the following: t= 90 n ab=100 cm ac 140 cm ? =25. determine forces f_ab, f_ac, and f_bc in n in members ab, ac, and bc.

Acircular aluminum shaft mounted in a journal is shown. the symmetric clearance gap between the shaft and journal is filled with sae 10w-30 oil at t 30°c. the shaft is caused to turn by the attached mass and cord. develop and solve a differential equation for the angular speed of the shaft as a function of time.

An electrical kettle is made out of stainless steel, weighs two pounds (when empty) with a heating element that consumes 2 kw of electricity. assuming that the water and the kettle are at the same uniform temperature at any moment of time, calculate the shortest possible time to bring 2 quarts of water from room temperature to the onset of boiling.

Agas mixture with a compostion of 55 methane, 30% propane, and 15 butane by volume) is compressed from 1 bar and 25°c to 9bar in a compressor with an isentropic efficiency of 85%. the environment has a temperature of to25 c. determine (a) the exit temperature of the mixture (b) the specific work required to run the compressor (c) the specific entropy generation of the process (d) the specific exergy destruction of the process (e) the second law efficiency of the compressor