Chapter 1: 6, 10, 11, 47, 48
6) The Mach number is defined as the ratio of flow speed to the speed of sound (Ma = V/c). When Ma is
much larger than a value of 1, the flow is hypersonic, which means a Mach number of 2 indicates a
hypersonic flow.
10) A boundary layer is the flow region adjacent to the wall of the system where its viscous effects are
most significant. This is caused by surface drag, which is the force that a fluid exerts on the surface in the
flow direction.
11) Steady flow refers to a state of flow in which there is no change of properties, velocity, or temperature
at a point with time
47) Accuracy is related to readings being more or less close to the true value, whereas precision is less
related to any true value, and instead related to readings being averaged more closely. Accuracy error is
associated with repeatable, fixed errors, and precision error is associated with unrepeatable, random
errors. A measurement can be precise while also being inaccurate. For example, when shooting darts at a
board, one can be precise with throwing their darts in a similar spot each time, but always miss. As long
as the person continuously throws their dart more or less in the same region at the far edge of the board,
the person is precise, but inaccurate.
48) When a physical problem arises, first identify the important variables. Then make reasonable
assumptions and approximations with the information given. Finally, apply any relevant physical laws.
Thi method will then derive a differential equation.
Chapter 2: 23, 52, 78, 81, 120, 124
23) Cavitation is a phenomenon that generates highly destrucitve and high pressure waves, and it is
caused by vapor bubbles collapsing from low pressure regions.
52) Sound is an infinitesimally small pressure wave which travels through a medium, and this pressure
wave may be caused by a small disturbance. Because sound waves travel through a medium, a vacuum
does not create any medium for a sound wave to travel through, thus, sounds cannot travel through a
vacuum.
78, 81, 120, 124