Author Question: A 30-year-old woman takes a trip on a rocket, leaving her 20-year-old brother behind. She travels at ... (Read 56 times)

Marty · **on:** Jul 28, 2018

A 30-year-old woman takes a trip on a rocket, leaving her 20-year-old brother behind. She travels at a speed of 0.8 c, and is gone 20 years, according to the younger brother. When she returns, how many years older/younger is she than her brother?
a. 2 years younger
b. 2 years older
c. 3 years older
d. 10 years older
e. 8 years older

Question 2

A spaceship moving past the Earth with a speed of 0.800 c signals to the Earth with pulsed laser photons emitted at 10.0-second intervals according to the spaceship's clock. According to observers on Earth who see the flashes, the time interval they measure is
a. 13.4 s
b. 16.7 s
c. 12.5 s
d. 9.70 s
e. 6.03 s