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 0.40 ×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)?

Acompressor compresses a gas, a pump compresses a liquid. for a given pressure ratio, why does it take more work to compress a gas in a compressor than a liquid in a pump? a)- for a given pressure ratio the average specific volume for a gas is much higher than the average specific volume for a liquid. b)- there is no difference. the only difference is the amount of heat generated (not work) c)- for a given pressure ratio the average volurge for a gas is much higher than the average volume for a liquid. d)-there is no difference