1. TUTORIAL WEEK 1 PLEASE REFER TEXTBOOK FOR DETAILS ON EACH QUESTION. Thermal Fluid Science, Cengel, Turner, Cimbala, 3 rd Edition.

2. QUESTION 1-2C On a downhill road the potential energy of the bicyclist is being converted to kinetic energy, and thus the bicyclist picks up speed. There is no creation of energy, and thus no violation of the conservation of energy principle. Why does a bicyclist pick up a speed on a downhill road even when he is not pedalling? Does this violate the conservation of energy principles?

3. Q 1-5C How does “heat transfer” differ from “thermodynamics”. Thermodynamics deals with the amount of heat transfer as a system undergoes a process from one equilibrium state to another. Heat transfer, on the other hand, deals with the rate of heat transfer as well as the temperature distribution within the system at a specified time.

4. Q 1-6C What is the driving force for HT, EC and FF? The driving force for heat transfer is the temperature difference. (b) The driving force for electric current flow is the electric potential difference (voltage). (a) The driving force for fluid flow is the pressure difference.

5. Q 1-7C Why is Heat Transfer a nonequilibrium phenomenon? Heat transfer is a non-equilibrium phenomena since in a system that is in equilibrium there can be no temperature differences and thus no heat flow.

6. 1-8C No, there cannot be any heat transfer between two bodies that are at the same temperature (regardless of pressure) since the driving force for heat transfer is temperature difference.

7. 1-14 The variation of gravitational acceleration above the sea level is given as a function of altitude. g = a – bz; a = 9.807 m/s 2 & b = 3.32 * 10 -6 s -2 Determine the height above sea level where the weight of an object will decrease by 1%? W = mg = m(a-bz) ; At z = z 1 = 0 m, W = mg = ma. Body weight decrease by 1 %, W 2 = 0.99W at z = z 2 Altitude at 1% weight reduction? 0.99W = 0.99ma = m (a-bz 2 ) Therefore, z 2 = (a – 0.99a)/b = 29,539 N.

8. 1-17 Throw 5 kg stone upward with a force of 150 N. g=9.79ms -2 ∑F = ma Y is positive upwards, Therefore, ∑F = Fup – Fg= 101.05 N 101.05 N = ma Therefore, a = 20.2 ms -2

9. Q 9-3c WHAT IS NO SLIP CONDITION? Analysis a fluid in direct contact with a solid surface sticks to the surface and there is no slip. This is known as the no-slip condition, and it is due to the viscosity of the fluid. There is no such thing as an inviscid fluid, since all fluids have viscosity.

10. Q 9-22C Viscosity, “stickiness” or “resistance to deformation” of a fluid. Due to the internal frictional force, between different layers Viscosity, cohesive forces between the molecules, liquids, and molecular collisions in gases.

11. Q 9-23C Fluids,shear stress, linearly proportional to the velocity gradient (strain rate) are called Newtonian fluids.

12. Q 9-25C The dynamic viscosity of liquids decreases with temperature. (b) The dynamic viscosity of gases increases with temperature. How does viscosity change with temperature?in fluid and gas.

13. Q 9-27C

14. Ans 9-27C (A)

15. Ans 9-27(B)

16. QUIZ Q 9-28 Submit before 18/07/08

17. QUIZ Q 9-29 Submit before 18/07/08