Engineering in Kenya

# Important Formulas of Physics

Posted by on Sep 6, 2011 in Physics | 0 comments

There are many important Formulas of Physics, considering the fact that physics as a subject is very wide and certain areas of physics draw connections from other areas of the same. The Formulas of Physics are categorized topically. Engineering in Kenya has more articles.

# Part 1 of Formulas of Physics

Formulas of Physics; Work & Energy From the knowledge of the law of conservation of energy, it is obvious that energy is always conserved; it can be transformed thou.

The product of a force and the displacement from its original position is called work. If one is pushing a heavy block across a room, then the further one moves, the more the work one does in Formulas of Physics.

I.e. work = force × distance moved

W = F × S

Energy on the other hand comes in many ways. Those that are discussed here are kinetic energy and potential energy. For normal kinetic energy;

Transitional kinetic energy = (mv 2)/ 2

Rotational kinetic energy = (Iw2)/ 2

For rotational kinetic energy in Formulas of Physics, I is the moment of inertia of an object (it is easier to understand moment of inertia by considering it to be similar to mass in transitional kinetic energy) and w is the angular velocity of the object. For potential energy;

Gravitational potential energy = mgh, where g is the gravitational pull and h the height of the object from the ground in Formulas of Physics.

Elastic potential energy = (k L2)/ 2, where k is spring constant and L the length of spring.

Formulas of Physics; Power Power is work done per unit time. The unit of power in Formulas of Physics is ‘watt’ or ‘horsepower’; 1 horsepower (hp) = 746 Watts

Power = work/ time; P = W/ t.

Since work is energy consumed over a certain distance, time is also a factor and thus power can also be defined with the confines of energy, i.e. P = E/ t

## Part 2 in Formulas of Physics

Formulas of Physics

Formulas of Physics; Circular motion

Given that V is the tangential velocity of an object, a is the centripetal acceleration, F is the centripetal force acting on the object, r is the radius of the circle of rotation and m the mass of the object;

a = V2 / r                                                                                                                                                            F = ma = mV2/r

Formulas of Physics; Gravitation

Kepler’s Laws
These laws in Formulas of Physics major on the behavior of space i.e. their movements and are as follows: -

• The orbit of any planet is elliptical and has the sun at one of its foci.
• Each planet’s movement is in such a way that the imaginary line joining it and the sun sweeps out equal areas at equal periods.
• The square of the period of revolution any planet about the sun is proportional to the cube of its mean distance from the sun in Formulas of Physics.

Newton’s law of universal gravitation

Every particle in the universe attracts another with a force directly proportional to the product of their masses and inversely proportional to the square of their separation.  Therefore, for Formulas of Physics if F is the force, g is the acceleration due to gravity, G is the universal gravitational constant (6.67×10-11 N.m2/kg2), m is the mass and r is the distance between two objects, then;

F = (G m1 m2)/ r2

Acceleration due to gravity

Acceleration due to gravity differs with the position on the earth’s surface in Formulas of Physics. Outside the earth, the acceleration due to gravity is the same as it would be if the entire mass of the earth were to be concentrated at its center. Given that the acceleration due to gravity is g’ at a radius r outside the earth, the earth’s radius being re and the acceleration due to gravity at the earth’s surface g;  g’ = (re2/ r2) × g
Inside the earth, the parameters are different. If r represents the radius of the point inside the earth, then;                  g’ = (r/ r) × g

For the formulas above in Formulas of Physics, the acceleration due to gravity g’ equals the acceleration due to gravity due to the earth’s surface g.

### Conclusion on Formulas of Physics

The above Formulas of Physics are well derived and an important part of engineering.