The most underlying feature of machines is
A) energy conservation.
B) that energy input always equals energy output.
C) that power input always equals power output.
D) all of the above
E) none of the above
Answer: A
You might also like to view...
As the polar icecaps melt, the resulting water spreads over the entire Earth. This new mass distribution tends to make the length of a day
A) longer. B) shorter. C) none of these
RC Circuits: For the circuit shown in the figure, C = 13 µF and R = 7.6 M?. Initially the switch S is open with the capacitor charged to a voltage of 80 V. The switch is then closed at time t = 0.00 s. What is the charge on the capacitor 40 s after closing the switch? 
A. 3300 µC B. 3100 µC C. 2900 µC D. 2700 µC E. 2500 µC
Angular Momentum: Three solid, uniform, cylindrical flywheels, each of mass 65.0 kg and radius 1.47 m, rotate independently around a common axis through their centers. Two of the flywheels rotate in one direction at 8.94 rad/s, but the other one rotates in the opposite direction at 3.42 rad/s. Calculate the magnitude of the net angular momentum of the system.
A. 1020 kg ? m2/s B. 1500 kg ? m2/s C. 975 kg ? m2/s D. 940 kg ? m2/s
After atoms form at 300,000 years into history, then the Universe becomes what?
A.) Empty. B.) Opaque. C.) White. D.) Dead. E.) Transparent.