An internal combustion engine generates the power of 28 kW at crank shaft angular velocity of 3100 rpm. This power is transmitted to the drive shaft via a multi-plate friction clutch (based on the design shown in Figure QA-1). New friction disks with outer and inner radii of 230 mm and 190 mm, respectively, are engaged with actuation force of 700 N. The coefficient of friction between the friction surfaces is 0.32. a) Determine the number of contact pairs required. b) With the help of a plot demonstrate the dependency of the actuation force on the number of contact pairs. How do you describe their relationship? The plot should have suitable axis title and units. After using the clutch for extended time, each friction surface is worn by 1.5 mm. If the actuation force is generated via 4 springs with stiffness of 12 kN/m: c) Find the maximum power that can be transmitted by the clutch without slip after the disks are worn Output shaft Flywheel Pressure plate Figure QA-1