Science

Katherine Johnson - A brilliant mind

Katherine Johnson was an American mathematician who calculated and analyzed the flight paths of many spacecraft during her more than three decades with the U.S. space program. Her work helped send astronauts to the Moon.   Read More

What is the maximum elongation of the spring ?

Assume we have 2 objects of the same mass m1=m2=m=0,5 kg which are attached by a spring of k=2,5N/m. Each object feels.. Read More

Shape of a hanging rope between two points - Mathematical analysis

Let's assume that we take a rope (or a chain as shown in the picture) and hang it up between two distinct points. We want to find the shape of the rope. What equation describes it?  Read More

The initial acceleration of a 3-body system

Assume that we let the system of the picture free. What will the initial acceleration of m be?

In a small time interval Δt, the length of the rope on top of object M is X-x, where X is the coordinate of M and x... Read More

Centripetal force of an object in an arbitrary curve

Let's assume that an object moves in an arbitrary curve which is described by y=y(x). We want to find the centripetal force that acts on the object in any point.  Read More

How to ease pressure on food supply - Science Daily

The shoots of plants get all of the glory, with their fruit and flowers and visible structure. But it's the portion that lies below the soil -- the branching, reaching arms of roots and hairs pulling up water and nutrients.   Read More

Electric field of infinite charge distribution - Gauss Law method 

Assume an infinite charge distribution that lies on the xy plane. If the charge density is σ, then what is the electric field of the distribution ?   Read More

A Falling Chain - Maximum reaction force

A homogenous chain of mass density ρ and length L is kept vertical above a horizontal level. We let the chain free. What is the maximum reaction force of the horizontal level ?   Read More

Hanging chain - Where is the tension greatest ?

A chain hangs between two points in the same horizontal line. We want to compare the tension of the chain in 3 different points (A, B and C). Point C is lower than B and point B is lower than A.   Read More

Steven Weinberg - Nobel Prize winning physicist dies at 88

What a great physicist! I first read for him in the biography of Dimitri Nanopoulos who stated that they were very close friends and had worked many times together. Nanopoulos description of Weinberg made me curious to read more about this great theoretical physicist Read More

How to vaccinate the whole world - The Economist 

One of the biggest challenges that humanity has faced the past centuries is the "victory" against the COVID-19 virus. Numerous attempts have been made the past year, and fortunately scientists have found the vaccine to prevent COVID-19.  Read More

Mathematical analysis of the motion of a homogenous rotating hemisphere

Assume a homogenous hemisphere of radius R, that can rotate around a horizontal axis, inside the homogenous gravitational field of Earth (g). If we define a coordinate system, starting from point O(0,0,0) as shown in the figure below... Read More

Point Transformation of Lagragian Function

We generally know that Newton's II Law varies when we change the coordinate system. For example Newton's Law in Cartesian coordinates takes the popular form (F=mx''=mα). But if we express it in polar coordinates, the usual form changes.   Read More

Is COVID-19 over ? - Study of Harvard's Chan School of Public Health

According to recent study of William Hanage, professor in Harvard Chan School of Public Health, corona virus is still not over. The new Delta variant, is quite more transmissible than original virus. Read More