Two friends, Sungyoung and Azhar are initially 10 years old. While Azhar remains on Earth, Sungyoung rides on a spaceship which travels away from Earth at a speed of 1c for 5years (as measured by Azhar), then immediately turns around and comes back at 1c. When Sungyoung returns, Azhar is 2*5 years older than when Sungyoung left. How old is Sungyoung upon his return?

Twins who are 19.0 years of age leave the earth and travel to a distant planet 12.0 light-years away. Assume that the planet and earth are at rest with respect to each other. The twins depart at the same time on different spaceships. One twin travels at a speed of 0.905c, and the other twin travels at 0.407c. (a) According to the theory of special relativity, what is the difference between their ages when they meet again at the earliest possible time? A₂-A₁ = (b) Which twin is older?

A spaceship moves past Earth with a speed of 0.808c. As it is passing, a person on Earth measures the spaceship's length to be 68.7 m. (a) Determine the spaceship's proper length (in m). m (b) Determine the time (in s) required for the spaceship to pass a point on Earth as measured by a person on Earth. s (c) Determine the time (in s) required for the spaceship to pass a point on Earth as measured by an astronaut onboard the spaceship.

An astronaut travels to the next star at 0.95c and back. He notices that hishike took him 11 years. When he returns, what will be the period of timethat will have passed on Earth during his absence?

1. An astronaut travels to a distant star with a speed of 0.46c relative to Earth. From the astronaut's point of view, the star is 4.40 ly from Earth. On the return trip, the astronaut travels with a speed of 0.90c relative to Earth. What is the distance covered on the return trip, as measured by the astronaut? Give your answer in ly f60 ss 0 ssf60* f60 ss 0 ssf6 ssf60 ssf6Q

Leo and Christian are twins. At the age of 30, Leo left for a round trip to a distant star in a spaceship at a speed of 0.95c relative to Earth. The trip took 20 years according to the ship-board clock. Find their ages when Leo returns.

A very fast-moving train car passes you, moving to the right at 0.50c. You measure its length to be 12 m. Your friend David flies past you to the right at a speed relative to you of 0.80c. How long does David measure the train car to be?

Twins who are 19.0 years of age leave the earth and travel to a distant planet 12.0 light-years away. Assume that the planet and earth are at rest with respect to each other. The twins depart at the same time on different spaceships. One twin travels at a speed of 0.867c, and the other twin travels at 0.515c. (a) According to the theory of special relativity, what is the difference between their ages when they meet again at the earliest possible time? A₂-A₁ = i (b) Which twin is older?

An alien spaceship traveling at 0.560c toward the Earth launches a landing craft. The landing craft travels in the same direction with a speed of 0.760c relative to the mother ship (as measured by aliens on the mother ship). As measured on the Earth, the spaceship is 0.130 ly from the Earth when the landing craft is launched. (a) What speed do the Earth-based observers measure for the approaching landing craft? 0.926 C (b) What is the distance to the Earth at the moment of the landing craft's launch as measured by the aliens (mother ship)? 0.108 ly (c) What travel time is required for the landing craft to reach the Earth as measured by the aliens on the mother ship? 0.19 Your response differs from the correct answer by more than 100%. yr (d*) What travel time is required for the landing craft to reach the Earth as measured by Earth-based observers? yr (e*) What travel time is required for the landing craft to reach the Earth as measured by those on the landing craft? yr

John, in his spaceship, observes as Sally, in her spaceship, passes him at a speed of v=0.8c. John who was born and raised on his spaceship, is 20 years old. According to Sally, how old is he? How many birthday parties should he have had and how many presents should Sally have sent him?