You used density, because water/ice has a density of 1, and ice will sink in anything with a lesser density
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



Answer:
A-Caclcuate the potential energy of the ball at that height
Explanation:
(a). Mass of the Body = 10 kg.
Height = 10 m.
Acceleration due to gravity = 9.8 m/s².
Using the Formula,Potential Energy = mgh
= 10 × 9.8 × 10 = 980 J.
(b). Now, By the law of the conservation of the Energy, Total amount of the energy of the system remains constant.
∴ Kinetic Energy before the body reaches the ground is equal to the Potential Energy at the height of 10 m.
∴ Kinetic Energy = 980 J.
(c). Kinetic Energy = 980 J.
Mass of the ball = 10 kg.
∵ K.E. = 1/2 × mv²
∴ 980 = 1/2 × 10 × v²
∴ v² = 980/5
⇒ v² = 196
∴ v = 14 m/s.
Answer:
The magnification is a function of the lenses in the objective and the eyepiece, so the magnification of the two must be multiplied to obtain the total magnification possible. So, for example, if the objective lens was 4X and the eye piece lens was 10X, the total magnification would be 40. (4 x 10 = 40)
Explanation:
Answer:
Recoil speed,
Explanation:
Given that,
Mass of the comet fragment, 
Speed of the comet fragment, 
Mass of Callisto, 
The collision is completely inelastic. Assuming for this calculation that Callisto's initial momentum is zero. So,

V is recoil speed of Callisto immediately after the collision.

So, the recoil speed of Callisto immediately after the collision is 