Physics

Friction does NOT vary depending upon whether an object is pushed or pulled. The frictional force (static or dynamic) is proportional to the normal force, the force that counteracts and exactly matches the weight of an object that is at rest (or moving at constant velocity). The frictional force will oppose the direction of the force applied to an object to move it. It matters not whether the object is pulled (using a tensile force) or pushed (using a compressive force).

Gravitational force depends on distance and mass. Thus, the formula for calculating gravitational force between 2 objects with a given distance: G [(mass 1) (mass 2)]/distance squared. G is universal gravitational constant: 6.67x10 raised to -11 power. Sorry if it's a little confusing to read...since I can't do basic math operations here.

The fireworks creators have worked many decades to figure these things out. There are several factors. The individual little bursts are wrapped separately. They are then arranged around a core in the shape desired and the propellant charge is placed in the middle. When it goes off it lights the individual bursts and propels them out in the shape desired. In additions to the hearts and stars, a maple leaf is popular in Canada.

Actually, substances can exist in all three states of matter simultaneously if the conditions are right. The triple point of a substance is the temperature and pressure at which all three states occur in equilibrium. Water can exist in natural environments in all three states of matter -- solid (ice), liquid, and gas (steam or water vapor).

By the way, when you put ice in a glass of water to create "ice water," the ice and water coexist awhile; that is, the ice stops melting. Water in both liquid and solid forms exists in the glass. The temperature of the ice and water is just slightly above zero degrees Celsius.

This makes eclipses rarer. If the moon's orbit were co-planar with earths, eclipses would happen every month, at the New Moon.

This is not a myth. It drains counter clockwise in the southern hemisphere and water drains clockwise in the northern hemisphere. It also drains straight down at the equator, it doesn't spin.

Fluorescence is strong in systems in which emission occurs from the state with the lowest energy.

The MeV means million electron volts. It's a measure of the energy the energy in the photon, which is a quantum (or specific quantity) of electromagnetic energy.

This 1 mega electron volt = 1.60217646 × 10-13 joules of energy.

In a nutshell, the power (measured in watts) dissipated by a resistance is directly proportional to the square of the current (measured in amperes or amps) flowing through that resistance.

It is given by the formula P = I2R, where P is the power in watts, I is the current in amps, and R is the resistance in ohms. For example, if two amps are flowing through a 10-ohm resistor, then the power dissipated by the resistor is 22 * 10 = 40 watts.

See also the Web Links to the left of this answer for more information.

The asteroid will always take the path minimizing its Lagrangian, known as the least action principle in Lagrangian mechanics. With conservative forces, there are four basic shapes for two different cases. Either the asteroid is trapped in the gravitational pull of an object, or it is not trapped. If the asteroid's energy is low enough to be trapped, then it can have either a circular or elliptical orbit. If it is not trapped, then this 'free asteroid' (much like a free electron) can have either an parabolic or a hyperbolic path. Much of this information came from "Classical Mechanics" by kibble and Berkshire (although there are much better books).

On earth free fall acceleration is 9.81 meters per second per second or 32.2 feet per second per second, not including air resistance.

Around these parts, free fall acceleration is the acceleration due to earth gravity on a body that is not acted on by an outside force (like air resistance or a bungee tether). The actual value is cited in the earlier part answer.

Shaft power P = (2(pi) * (angular Speed in rpm) * (Torque at shaft))/ 60

Torque of a solid shaft is given by (pi/16)* (Shear stress of material of shaft) * (Dia of shâft3)

Actually an isolation transformer may be physically the same as a Step up/Step Down transformer. The main difference is in the way they are used.

Another difference is that in a normal transformer there will be capacitance between the 2 windings, between the windings and core, between the core and shell, etc.

These capacitances bring in high frequency noise from outside, which will be transmitted in the secondary circuit. So [in an isolation transformer] wires are connected between each component, (not direct contact, but with insulation present). This permits a leakage current and eliminates unnecessary capacitance.

A "balanced field" with respect to aircraft takeoff performance refers to the minimum length of runway that will allow for an aircraft to accelerate to V-1 (decision speed), experience failure of the critical engine, and then either stop in the remaining runway or continue to a successful takeoff meeting all applicable takeoff performance criteria.

Fixed pulleys are used to change the direction of a force.

Atoms are made up of protons, neutrons, and electrons. The protons and neutrons are found together in the core of the atom, called the nucleus, which is in the center. The electrons are found moving around the nucleus (at different energy levels) in what is called the electron cloud.

Note that in hydrogen most all of it is made up of just a lone proton and an electron. There are no neutrons in the most common isotope of hydrogen (1H).

Protons and neutrons, which are called nucleons when they're found in an atomic nucleus, are further made of still smaller subatomic particles called quarks.

When a reference is used to four-dimensional co-ordinates, it is likely that what is referred to, is the three spatial dimensions plus a time-line.