Một vật khối lượng m đứng yên trên đỉnh một mặt phẳng nghiêng nhờ lực ma sát. Cho biết chiều dài mặt phẳng nghiêng $ = 1 m, góc a = 30", hệ số ma sát giữa vật và mặt phẳng nghiêng 1 = 0,6. Hỏi: Mặt phẳng nghiêng có thể chuyển động với gia tốc thua (so với mặt đất) là bao nhiêu để vật vẫn đứng yên trên nêm Nếu gia tốc chuyển động của mặt phẳng nghiêng là 0, = m/s thì sau baonhiêu lầu vật sẽ trượt đến chăn mặt phẳng nghiêng

What is the conversion factor between kg/m^3 and g/m^3. express your experimental values for the densities in kg/m^3.

In a steady-flow steam power plant system, two adiabatic high-pressure and low-pressure turbines ane used to generate power. superheated steam enters the high-pressure turbine at 8 mpa and 550°c. the steam expands in the high-pressure turbine to a saturated vapor at 3 mpa. in order to increase the powe generation of the power plant, another steam turbine working in a lower pressure ranges is deployed. the outlet vapor from the first turbine is heated up at a boiler to the temperature of 500 c at the constant pressure of first turbine's outlet (3 mpa). then, the vapor enters the second turbine and produces extra work. the exit conditions of the second turbine are 5o kpa and 90 percent quality. if the total power output of the power plant is 25 mw, determine a) the mass flow rate of the water (kg/s). b) heat transfer rate in the boiler (mw). (30 points) 3 mpa 00 c 8 mpa s0 c high pres turbine low pres boiler turbine 50 kpa 3 mpa 09 saturated vapor t heat engine, shown in the figure, operates between high temperature and low temperature of through a heat 4. a carnot tn and tu respectively. this heat engine receives energy from a heat reservoir at t exchanger where the heat transferred is proportional to the temperature difference as ? = k (z,-7, ). it rejects heat at a given low temperature tl. to design the heat engine for maximum work output, find the high temperature, th, as a function of tes and t. (15 points) qe

The desk has a weight of 75 lb and a center of gravity at g. determine the initial acceleration of a desk when the man applies enough force f to overcome the static friction at a and b. also, find the vertical reactions on each of the two legs at a and at b. the coefficients of static and kinetic friction at a and b are ms = 0.5 and mk = 0.2, respectively