4. A 25-year-old astronaut says good-bye to her 5-year-old nephew. She boards a space shuttle for a round trip flyby of a distant planet. When she returns, she and her nephew are of the same age- 30 years old. At what speed v/c was the astronaut cruising? Show all your work. = 1.675 x 10-27kg) to have a wavelength = 5. What should be the speed of a neutron (mass 10-10m that is comparable to the size of atoms? Show all your work.