7. The surface finish for the cylinder walls usually depends on the O A. type of engine oil used.
O B. sharpness of the cylinder bore edges.
O C. type of piston rings used
O D. cylinder wall-to-piston clearance.

Air flows over a heated plate àt a velocity of 50m/s. the local skin factor coefficient at a point on a plate is 0.004. estimate the local heat transfer coefficient at this point.the following property data for air are given: density = 0.88kg/m3 , viscosity 2.286 x 10 ^-5 kgm/s , k = 0.035w/mk ,cp = 1.001kj/kgk. use colburn reynolds analogy.