On a day when the speed of sound in the upper air is 320 m/s, you fly coast to coast in the United States, a distance of about 4 850 km, in about one hour, if the Mach number for the speed of your airplane is about
a. 1.
b. 2
c. 3
d. 4
e. 5.
d
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Find the work W done by the "ideal" heat engine.
A bungee jumper attains a speed of 30 m/s just as the bungee cord begins to stretch. If the period of stretch is 2 s while coming to a halt, the jumper's average deceleration is about
A) 0.5 g. B) g. C) 1.5 g. D) 2 g.
"Hybrid drive" automobiles use
A) hydrogen fuel that burns much like gasoline within an engine that drives the wheels. B) natural gas fuel stored at high pressure. C) a small gasoline engine that drives an electric generator. D) large storage batteries that are recharged by plugging them into a wall socket. E) small batteries that energize a small gasoline engine that drives the wheels.
The focal lengths of the objective and the eyepiece in a microscope are 0.29 cm and 2.50 cm, respectively. An object is placed at 0.30 cm
from the objective lens and the image of this object is viewed with the eyepiece adjusted for minimum eyestrain (with the eye focused at the far point). The near point of the person using the microscope is 25 cm and the far point is at infinity. What is the final overall magnification of the microscope? A) -190 x B) -240 x C) -300 x D) -320 x E) -470 x