We can derive the equation of motion for mechanical systems in a Galileo universe with ι time dimensions and χ space dimensions by generalizing the principle of relativity and Hamilton’s principle.
Suppose a supersonic airplane has Mach number M. It flies horizontally. At some time, it flies past over your head at height h. Then, the distance between you and it when you have just heard it is Mh.
Sometimes the curvature radius of a curve can be found by using physical methods although it seems that you must use calculus to find it. In this article, the curvature radius of the curve x2=2py at the point where the curvature radius is smallest is found by using physical methods without using calculus (with only high school knowledge). The answer is that the smallest curvature is exactly p, and the point with smallest curvature is the vertex.
In the vacuum, inside a fixed ring of radius R with fixed charge Q uniformly distributed, there is a point charge with charge q and mass m moving in the plane of the ring due tue the electrostatic force. It moves in the small region around the center of the ring, and the motion is periodic along a closed curve. The area of the region enclosed by the curve is S. Denote the distance from the center to the point charge as r, and r≪R. Find the magnetic induction B at the center of the ring.
By recursively integrating according to xn+1(t):=∫t0tf(xn(s),s)ds+C from x0(t0):=C, we can get the solution of the ODE
x′(t)=f(x(t),t) with initial conditions x(t0)=C as the limit of the sequence of functions.
To illustrate the concept about non-uniform elements, we study a simple problem: suppose a uniform heavy elastic rope has mass m, original length L0, and stiffness k, and find the mass distribution and length of it when hung vertically. We can use the element method to solve this problem, but the elements are non-uniform in terms of length. The elements add up to get the total length L=2kmg+L0.
In this article, we will find that the inertia matrix naturally appears when we calculate the kinetic energy T or the angular momentum M of a rigid body. Then, we introduce the concept of principal inertia Jpri. We also study how the inertia matrix changes under translations and rotations and how those transformations may lead to conclusions that can help us simplify the calculation of inertia matrices.
The Hölder mean of x with weights w and a parameter p is defined as Mp,w(x):=(w⋅xp)p1, and the value at p=−∞,0,+∞ are defined by the limits. We can prove using Jensen’s inquality that the Hölder mean increases as p increases. This property can be used to prove HM-GM-AM-QM inequalities.
The function (1−z)n+1∑k=1∞knzk is a polynomial of degree n w.r.t. z, and the sum of its coefficients is n!. This turns out to be properties of Eulerian numbers.
I use udev and systemd to send a notification to my phone via ntfy automatically whenever my laptop is discharging.
We can derive the equation of motion for mechanical systems in a Galileo universe with time dimensions and space dimensions by generalizing the principle of relativity and Hamilton’s principle.
Suppose a supersonic airplane has Mach number . It flies horizontally. At some time, it flies past over your head at height . Then, the distance between you and it when you have just heard it is .
Sometimes the curvature radius of a curve can be found by using physical methods although it seems that you must use calculus to find it. In this article, the curvature radius of the curve at the point where the curvature radius is smallest is found by using physical methods without using calculus (with only high school knowledge). The answer is that the smallest curvature is exactly , and the point with smallest curvature is the vertex.
In the vacuum, inside a fixed ring of radius with fixed charge uniformly distributed, there is a point charge with charge and mass moving in the plane of the ring due tue the electrostatic force. It moves in the small region around the center of the ring, and the motion is periodic along a closed curve. The area of the region enclosed by the curve is . Denote the distance from the center to the point charge as , and . Find the magnetic induction at the center of the ring.
By recursively integrating according to from , we can get the solution of the ODE
with initial conditions as the limit of the sequence of functions.
To illustrate the concept about non-uniform elements, we study a simple problem: suppose a uniform heavy elastic rope has mass , original length , and stiffness , and find the mass distribution and length of it when hung vertically. We can use the element method to solve this problem, but the elements are non-uniform in terms of length. The elements add up to get the total length .
In this article, we will find that the inertia matrix naturally appears when we calculate the kinetic energy or the angular momentum of a rigid body. Then, we introduce the concept of principal inertia . We also study how the inertia matrix changes under translations and rotations and how those transformations may lead to conclusions that can help us simplify the calculation of inertia matrices.
The Hölder mean of with weights and a parameter is defined as , and the value at are defined by the limits. We can prove using Jensen’s inquality that the Hölder mean increases as increases. This property can be used to prove HM-GM-AM-QM inequalities.
The function is a polynomial of degree w.r.t. , and the sum of its coefficients is . This turns out to be properties of Eulerian numbers.