A boxcar without a front or a back is moving toward the right. Two flashes of light move through the boxcar, one moving from back to front toward the right, the other moving from front to back toward the left. A passenger in the boxcar records how long it takes each flash of light to pass from one end of the boxcar to the other end. According to the passenger, which took longer?
a. the flash going from back to front
b. the flash going from front to back
c. They both took the same time.
d. It depends on whether the passenger is sitting at the front or the back of the boxcar.
c
You might also like to view...
Calculate the water side heat transfer coefficient and the coolant pressure drop per unit length of tube for the core of a compact air-to-water intercooler for a 3.7 MW gas turbine plant. The water flows inside of a flattened aluminum tube having the cross- section shown belowThe inside diameter of the tube before it was flattened was 1.23 cm with a wall thickness (t) of 0.025 cm. The water enters the tube at 15.6°C and leaves at 26.7°C at a velocity of 1.34 m/s.
GIVEN
Water flow in a flattened tube as shown above
Inlet temperature (Ti) = 15.6°C
Outlet temperature (To) = 26.7°C
Water velocity (V) = 1.34 m/s
FIND
(a) The heat transfer coefficient on the inside of the tubes hc
(b) The pressure drop per unit length (?p/L)
ASSUMPTIONS
Steady state
Fully developed flow
PROPERTIES AND CONSTANTS
From Appendix 2, Table 13, for water at the average temperature of 21.1°C
As measured in Earth's rest frame, a spaceship traveling at 0.964c takes 11.2 y to travel between planets. How long does the trip take as measured by someone on the spaceship?
A) 2.98 y B) 7.28 y C) 42.1 y D) 30.7 y
Which is the shorter time unit - a light-second, a light-minute, or a light-year?
a. light-second b. light-minute c. light-year d. None of the other choices are correct.
An electromagnetic wave is a result of electric and magnetic fields acting together
Indicate whether the statement is true or false