Complete question:
Part A:) The fictional rocket ship Adventure is measured to be 50 m long by the ship's captain inside the rocket.When the rocket moves past a space dock at 0.5c , space-dock personnel measure the rocket ship to be 43.3 m long. The rocket ship Adventure travels to a star many light-years away, then turns around and returns at the same speed. When it returns to the space dock, who would have aged less: the space-dock personnel or ship's captain?
Part B: What is the momentum of a proton traveling at 0.62 c ?
Answer
a)Who would have aged less=The Captain would have aged less
b) 
Explanation:
From the question we are told that
Length measured by captain 
Speed of rocket past tje space dock 
Length measured by space-dock personnel 
a)
Generally time moves slower when moving at speed of light, due to time dilation or variation.
Who would have aged less=The Captain would have aged less
b)
Generally the equation for Relativistic Momentum is mathematically given as



it has a rocky core so the gravity from that compacts the gases extremly tight
Chapter name please then I can answer
Answer:
Part a)

Part B)

Part c)

Explanation:
Part a)
As we know that

so we will have





Part B)
Angular speed of the yo-yo

so we have


Part c)
Tangential acceleration is given as



When you hold the ball, you have potential energy, when you drop the ball, you have kinetic.