Answer:
25.3 ft
Explanation:
The illustration of the problem is shown the attached image.
The length of the ladder can be calculated using the Pythagoras theorem:

The hypotenuse is the length of the ladder.

........1
Triangle ABC is similar to triangle AEF, hence:

BC =
.................2
Substitute 2 into 1
=
+ 
Let AE = x
= 
= 
Minimize L with respect to x.
2
= 
=
Answer:
F = 2.30 10⁴ N
Explanation:
The force required to link two gates must be equal to or greater than the electrostatic force of repulsion, because the protons have equal charges.
F = k q₁ q₂ / r²
Where k is the Coulomb constant that is worth 8.99 10⁹ N m² / C²
In this case the proton charge is 1.6 10⁻¹⁹ C and the distance between them is approximately the diameter of the core r = 10⁻¹⁵ m
Let's calculate
F = 8.99 10⁹ (1.6 10⁻¹⁹)² / (10⁻¹⁵)²
F = 2.30 10⁴ N
The bond strength must be equal to or greater than this value
<span>1.7 rad/s
The key thing here is conservation of angular momentum. The system as a whole will retain the same angular momentum. The initial velocity is 1.7 rad/s. As the person walks closer to the center of the spinning disk, the speed will increase. But I'm not going to bother calculating by how much. Just remember the speed will increase. And then as the person walks back out to the rim to the same distance that the person originally started, the speed will decrease. But during the entire walk, the total angular momentum remained constant. And since the initial mass distribution matches the final mass distribution, the final angular speed will match the initial angular speed.</span>