Power
a) is work times time.
b) is force divided by time.
c) has the same units of energy.
d) is work divided by time.
•
d
You might also like to view...
A radioactive sample is to be stored in a protective box with 4-cm-thick walls having interior dimensions 4 cm* 4 cm* 12 cm. The radiation emitted by the sample is completely absorbed at the inner surface of the box, which is made of concrete. If the outside temperature of the box is 25°C, but the inside temperature is not to exceed 50°C, determine the maximum permissible radiation rate from the sample, in watts.
GIVEN
A radioactive sample in a protective concrete box
Wall thickness (t) = 4 cm = 0.4 m
Box interior dimensions: 4 x 4 x 12 cm
All radiation emitted is completely absorbed at the inner surface of the box
The outside temperature of the box (To) = 25°C
The maximum inside temperature (Ti) = 50°C
FIND
The maximum permissible radiation rate from the sample, q (in watts)
ASSUMPTIONS
The system is in steady state
SKETCH
The volume of water displaced by a floating 20-ton boat
A) is 20 cubic meters. B) is the volume of 20 tons of water. C) is the volume of the boat. D) depends on the shape of the ship's hull. E) none of the above
A source emits sound at a fixed constant frequency f. If the source moves away from you, and at the same time you run away from the source, the frequency you hear is
a. the same as f c. lower than f b. higher than f d. unrelated to f
What clues do other Kuiper belt comets offer about the origin of the belt?
A. The similar characteristics of Kuiper belt objects such as travel direction, orbit inclination, stable orbital resonance with Neptune, and composition suggest that these objects have the common origin and were formed in the outer region of the solar system. B. The similar characteristics of Kuiper belt objects such as travel direction, orbit inclination, stable orbital resonance with Jupiter, and composition suggest that these objects were formed in the inner region of the solar system and than draged to the farther distance. C. Kuiper belt objects have different travel direction, orbit inclination, and composition. They also do not have orbital resonances with any of the planets. It suggest that these objects were formed outside the solar system and than attracted by the gravity of the Sun and jovian planets. D. Kuiper belt objects have different travel direction, orbit inclination, and composition. They also have orbital resonances with different jovian planets. It suggest that these objects were formed in different regions of the solar system and than draged to their present orbits.