Two twin sisters, Gwen and Jackie, are both 20 years old in the year 2050. Suppose that Jackie makes the round-trip to Vega, which is 25 light-years away, at an average speed of 0.9999c. Which of the following correctly describes the situation when Jackie returns to Earth? (Ages in this problem refer to biological ages, that is, how much time has passed for each sister since she was born.)
A) It's the year 2100. Gwen (who stayed home) is 70 years old, but Jackie is only a little older than her age of 20 when she left.
B) It's the year 2100 and both twin sisters are 70 years old.
C) It's the year 2100. Gwen is 70 years old. Jackie is 19.
D) According to Gwen, Jackie returns to Earth in the year 2100, but according to Jackie, she returns in the year 2051.
A) It's the year 2100. Gwen (who stayed home) is 70 years old, but Jackie is only a little older than her age of 20 when she left.
You might also like to view...
A coil in a magnetic field encloses a flux of 0.196 T·m2 when the angle between the normal to the coil and the direction of the magnetic field is 62.0°. What flux would go through the coil if the angle were changed to 38.9°?
a. 0.118 T·m2 b. 0.123 T·m2 c. 0.539 T·m2 d. 0.325 T·m2 e. 0.139 T·m2
If a convex lens were made out of very thin clear plastic filled with air, and were then placed underwater where n = 1.33 and where the lens would have an effective index of refraction n = 1, the lens would act in the same way
A. as a concave mirror in air. B. as a concave lens in air. C. as a convex lens in air. D. as a flat refracting surface between water and air as seen from the water side. E. as the glasses worn by a farsighted person.
Two spheres are cut from a certain uniform rock. One has radius 4.50 cm. The mass of the other is five times greater.
Find its radius.
Although the entire universe may be much larger than our observable universe, we can see only within our observable universe. The "boundary" of our observable universe is called
A) the cosmological horizon. B) the Big Bang. C) the lookback time. D) the singularity.