Questions from Thermal Fluid Science

Q: Stainless steel ball bearings (ρ = 8085 kg/m3 and

Stainless steel ball bearings (ρ = 8085 kg/m3 and cp = 0.480 kJ/kg·°C) having a diameter of 1.2 cm are to be quenched in water at a rate of 800 per minute. The balls leave the oven at a uniform temper...

Q: In a production facility, 1.6-in-thick

In a production facility, 1.6-in-thick 2-ft × 2-ft square brass plates (ρ = 532.5 lbm/ft3 and cp = 0.091 Btu/lbm·°F) that are initially at a uniform te...

Q: Long cylindrical steel rods (ρ = 7833 kg/m3 and

Long cylindrical steel rods (ρ = 7833 kg/m3 and cp = 0.465 kJ/kg·°C) of 8 cm diameter are heat treated by drawing them at a velocity of 2 m/min through an oven maintained at 900°C. If the rods enter t...

Q: An electronic device dissipating 25 W has a mass of 20 g

An electronic device dissipating 25 W has a mass of 20 g and a specific heat of 850 J/kg·°C. The device is lightly used, and it is on for 5 min and then off for several hours, during which it cools to...

Q: Reconsider Prob. 5–84. Using appropriate software, investigate

Reconsider Prob. 5–84. Using appropriate software, investigate the effect of the mass of the heat sink on the maximum device temperature. Let the mass of the heat sink vary from 0 to 1 kg. Plot the ma...

Q: If you ever slapped someone or got slapped yourself, you probably

If you ever slapped someone or got slapped yourself, you probably remember the burning sensation. Imagine you had the unfortunate occasion of being slapped by an angry person, which caused the tempera...

Q: Reconsider Prob. 2–41. Using appropriate software, investigate

Reconsider Prob. 2–41. Using appropriate software, investigate the effect of the spring force in the range of 0 to 500 N on the pressure inside the cylinder. Plot the pressure agains...

Q: Which of two gases—neon or air—requires less work

Which of two gases—neon or air—requires less work when compressed in a closed system from P1 to P2 using a polytropic process with n = 1.5?

Q: Which of two gases—neon or air—produces more work

Which of two gases—neon or air—produces more work when expanded from P1 to P2 in a closed system polytropic process with n = 1.2?

Q: Consider a classroom that is losing heat to the outdoors at a

Consider a classroom that is losing heat to the outdoors at a rate of 12,000 kJ/h. If there are 40 students in class, each dissipating sensible heat at a rate of 84 W, determine if it is necessary to...