Week 4 Energy Matter and the Four Forces

How has E=mc2 affected me?

Hmmmm, well Einstein’s equation dramatically shifted how we perceived energy a century ago. However, it is also associated in my mind the development of the atomic bomb. During World War II the equation appeared in a report presented to the US government prepared by physicist Henry DeWolf Smyth during the Manhattan project. The history is of course complex, Einstien himself was not directly involved, but his ideas were initially used by scientists in the development of atomic weapons theory.

http://www.universetoday.com/114617/a-fun-way-of-understanding-emc2/

Comparing the Four Forces of Nature

Gravitational force is relatively weak, but has a very long range. It is always attractive, and acts between any two pieces of matter in the Universe. Isaac Newton envisioned gravity as a pull between two objects that directly related to their respective masses and inversely related to the square of the distance separating them.  The laws of motion and gravity dontt apply to objects in high gravity or at high speeds, like the speed of light. Electromagnetic force causes electric/ magnetic effect such as repulsion between like charges. It is long-ranged, but relatively weaker than strong force. It can be attractive or repulsive, and acts only between pieces of matter carrying electrical charge.  Force that is excerted on the subatomic scale is explained through the phenomina of strong force. The force holding the nucleus together is called strong force.  Strong force is very strong, but microscopically short-ranged. It acts only over ranges of order 10-13 centimeters. Strong force is attractive, but can be repulsive in some circumstances. Lastly, weak force is responsible for radioactive decay and neutrino interactions. It has a very short range and is very weak.

Must Read: http://science.howstuffworks.com/environmental/earth/geophysics/fundamental-forces-of-nature.htm

What is the function of gravity?

Gravity is a natural phemomenon that is responsible for the attraction of objects in space. It is the description of the energy or attraction between objects. It is responsible for the creation of many of the structures in the universe- stars, galaxies, etc.. In our own bodies we experience the effects of gravity in a multitude of ways. One observable aspect of gravity is its role in walking. When we walk or run we can hit the ground without losing contact with it, but we also have to work against gravity with each step.