Week 4: Energy Matter & the Four Forces

·       How has e=mc² affected you?

·       This explanation seemed most relevant:

·       Mass-energy convertibility has far-reaching consequences. Your car's engine is powered by fossil fuel, which comes from prehistoric plants. The plants got their energy from sunlight, which was produced by nuclear fusion in the sun. So your car, and virtually all other activity on Earth, is ultimately powered byE=mc².

·       How would you compare the four “forces”?

Properties of the Fundamental Forces

• The strong interaction is very strong, but very short-ranged. It acts only over ranges of order 10^-13 centimeters and is responsible for holding the nuclei of atoms together. It is basically attractive, but can be effectively repulsive in some circumstances.
• The electromagnetic force causes electric and magnetic effects such as the repulsion between like electrical charges or the interaction of bar magnets. It is long-ranged, but much weaker than the strong force. It can be attractive or repulsive, and acts only between pieces of matter carrying electrical charge.
• The weak force is responsible for radioactive decay and neutrino interactions. It has a very short range and, as its name indicates, it is very weak.
• The gravitational force is weak, but very long ranged. Furthermore, it is always attractive, and acts between any two pieces of matter in the Universe since mass is its source.

·       What is the function of gravity?

Gravity is the force that attracts two bodies toward each other, the force that causes apples to fall toward the ground and the planets to orbit the sun. The more massive an object is, the stronger its gravitational pull.

Gravity is one of the four fundamental forces, along with the electromagnetic, strong and weak forces.

It is what causes objects to have weight. When you weigh yourself, the scale tells you how much gravity is acting on your body. The formula for determining weight is: weight equals mass times gravity. On Earth, gravity is a constant 9.8 meters per second squared, or 9.8 m/s2.