A car moving at 50 km/h skids 20 m with locked brakes. How far will it skid if its initial speed is 150 km/h?
A) 20 m
B) 60 m
C) 90 m
D) 180 m
Answer: D
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Methane gas absorbs the color ________, accounting for the colors of Uranus and Neptune
Fill in the blank(s) with correct word
Which of the following is true of chromatic aberration?
A) It mostly occurs in reflecting telescopes. B) It occurs when different colors are focused at slightly different distances. C) It is a natural phenomenon that occurs because of high turbulence in Earth's atmosphere. D) It is the main cause of seeing.
A hot-wire anemometer is used to determine the boundary layer velocity profile in the air flow over a scale model of an automobile. The hot-wire is held in a traversing mechanism that moves the wire in a direction normal to the surface of the model. The hot-wire is operated at constant temperature. The boundary layer thickness is to be defined as the distance from the model surface at which the velocity is 90% of the free stream velocity. If the probe current is I0, when the hot-wire is held in the free stream velocity, U?, what current indicates the edge of the boundary layer? Neglect radiation heat transfer from the hot-wire and conduction from the ends of the wire.
GIVEN • Thin, electrically-heated constant-temperature wire in air flow near an automobile model • Boundary layer thickness ° point when velocity (Uy) = 90% free stream velocity Vo • Probe current at U? = Io FIND • Probe current at edge of the boundary layer (Ib) ASSUMPTIONS • Radiation is negligible • Conduction from the ends of the hot-wire is negligible • Reynolds number is small
Answer the following statement(s) true (T) or false (F)
1. Equation E18.4 
is also solved by a function f (s), where s = t + x/c.
2. One can in principle create a purely electric traveling electromagnetic wave in empty space 