A cup that is 6.0 cm tall is in front of a concave lens. The image of the cup is 2.5 cm tall and 7.5 cm from the lens. What is the focal length of the lens?
A) -6.0 cm
B) -7.5 cm
C) -13 cm
D) +18 cm
E) +6.0 cm
C
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Mass on a Spring: A 92-kg man climbs into a car with worn out shock absorbers, and this causes the car to drop down 4.5 cm. As he drives along he hits a bump, which starts the car oscillating at an angular frequency of 4.52 rad/s. What is the mass of the car?
A. 890 kg B. 760 kg C. 920 kg D. 990 kg E. 1900 kg
A jet traveling at 1500 km/h passes overhead. The sonic boom produced is heard by
A) a listener on the ground. B) the jet pilot. C) both of these D) neither of these
A long cylindrical rod, 8 cm in diameter, is initially at a uniform temperature of 20°C. At time t = 0, the rod is exposed to an ambient temperature of 400°C through a heat transfer coefficient of 20 W/(m2 K). The thermal conductivity of the rod is 0.8 W/(mK) and the thermal diffusivity is 3 × 10–6 m2/s. Determine how much time will be required for the temperature change at the centerline of the rod to reach 93.68% of its maximum value. Use an explicit difference equation and compare your numerical results with a chart solution.
GIVEN • Cylindrical rod suddenly exposed to increased ambient temperature FIND (a) Time required for the centerline temperature change to reach 93.68% of its maximum value
The most common rocks on Earth's surface are
a. discordant. b. concordant. c. metamorphic. d. sedimentary.