If you see Al going to your left at exactly 0.99c and Bob going to your right at exactly 0.99c, Al will say that Bob is
A) going away from her at 1.98c.
B) going away from her at exactly 0.99c.
C) going away from her at exactly c.
D) going away from her at about 0.98c.
E) going away from her faster than 0.99c, but slower than c.
E
You might also like to view...
Water flowing through a pipe is heated by steam condensing on the outside of the pipe. (a) Assuming a uniform overall heat transfer coefficient along the pipe, derive an expression for the water temperature as a function of distance from the entrance. (b) For an overall heat transfer coefficient of 570 W/(m2 K), based on the inside diameter of 5 cm, a steam temperature of 104°C, and water-flow rate of 0.063 kg/s, calculate the length required to raise the water temperature from 15.5 to 65.5°C.
GIVEN
• Water flowing through a pipe steam condensing on the outside
FIND
(a) An expression for the water temperature as a function of distance from the entrance, Tw (x)
(b) For Overall heat transfer coefficient (U) = 570 W/(m2 K)
Inside diameter (D) = 5 cm = 0.05 m
Steam temperature (Ts) = 104°C
Water flow rate ( m w) = 0.063 kg/s
Water temperatures: Tw,in = 15.5°C Tw,out = 65.5°C
Find the length (L) required
ASSUMPTIONS
• A uniform overall heat transfer coefficient
SKETCH
PROPERTIES AND CONSTANTS
the specific heat of water at the mean temperature of 40°C (cpw) =4175 J/(kg K)
In our best current theory, the first quasars formed about:
A) 14.5 billion years ago. B) 13 billion years ago. C) 12 billion years ago. D) 11 billion years ago. E) 9 billion years ago.
The greatest inaccuracy in Copernicus' model of the solar system was that the planets
a. travel in circular orbits with uniform motion. b. traveled on epicycles whose centers followed orbits around the Sun. c. traveled in elliptical orbits. d. were allowed to travel backwards in their orbits. e. the planets orbited the Sun.
An electron of mass 9.11 × 10^–31 kg has a momentum of 2.06 × 10^–22 kg•m/s. What is its speed?
a. 0.800c b. 0.467c c. 0.602c d. It cannot have this momentum since it would require a speed greater than c.