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



Are you referring to the fact that water is a compound while hydrogen is an element? If I'm wrong just comment and clarify and I can edit it, I don't even know what kind of unit you're in. :)
Answer:
The change in volume is 
Solution:
As per the question:
Coefficient of linear expansion of Copper, 
Initial Temperature, T =
= 273 K
Final Temperature, T' =
= 273 + 100 = 373 K
Now,
Initial Volume of the block, V = 



where
V' = Final volume


Answer:
The capacity for doing work.
Explanation:
It has the forms kinetic, potential, thermal, electric, nuclear or other forms of energy.
<span>
The needle of a compass will always lies along the magnetic
field lines of the earth.
A magnetic declination at a point on the earth’s surface
equal to zero implies that
the horizontal component of the earth’s magnetic field line
at that specific point lies along
the line of the north-south magnetic poles. </span>
The presence of a
current-carrying wire creates an additional <span>
magnetic field that combines with the earth’s magnetic field.
Since magnetic
<span>fields are vector quantities, therefore the magnetic field of
the earth and the magnetic field of the vertical wire must be
combined vectorially. </span></span>
<span>
Where:</span>
B1 = magnetic field of
the earth along the x-axis = 0.45 × 10 ⁻ ⁴ T
B2 = magnetic field due to
the straight vertical wire along the y-axis
We can calculate for B2
using Amperes Law:
B2 = μ₀ i / [ 2 π R ]
B2 = [ 4π × 10 ⁻ ⁷ T • m / A ] ( 36 A ) / [ 2 π (0.21 m ) ] <span>
B2 = 5.97 × 10 ⁻ ⁵ T = 0.60 × 10 ⁻ ⁴ T </span>
The angle can be
calculated using tan function:<span>
tan θ = y / x = B₂ / B₁ = 0.60 × 10 ⁻ ⁴ T / 0.45 × 10 ⁻ ⁴ T <span>
tan θ = 1.326</span></span>
θ = 53°
<span>
<span>The compass needle points along the direction of 53° west of
north.</span></span>