The convection coefficient for flow over a solid sphere may be determined by submerging the sphere, which is initially at 25 °c, into the flow, which is at 75 °c, and measuring its surface temperature at some time during the transient heating process. if the sphere has a diameter of 0.1 m, a thermal conductivity of 22 w/(m·k), and a thermal diffusivity of 9.0 ×10-5 m2/s, at what time will a surface temperature of 60 ºc be recorded if the convection coefficient is 300 w/(m2·k)?

The mass flow rate of the fluid remains constant in all steady flow process. a)- true b)- false

Asingle-geared blanking press has a stroke of 200 mm and a rated capacity of 320 kn. a cam driven ram is assumed to be capable of delivering the full press load at constant force during the last 15 percent of a constant-velocity stroke. the camshaft has an average speed of 90 rev/min and is geared to the flywheel shaft at a 6: 1 ratio. the total work done is to include an allowance of 16 percent for friction a) estimate the maximum energy fluctuation b) find the rim weight for an effective diameter of 1.2 m and a coefficient of speed fluctuation of 0.10

An ideal otto cycle with air as the working fluid has a compression ratio of 8. the minimum and maximum temperatures in the cycle are 300 k and 1340 k. use constant specific heats at room temperature to determine (a) the amount of heat transferred to the air during the heat- addition kj/kg, (b) the thermal efficiency, and (c) the thermal efficiency of a carnot cycle ope limits. process, in rating between the same temperature