Fundamental Forces: Gravity, Electricity, and Magnetism
Fundamental Forces in Nature
Gravitational force and electromagnetic force are two fundamental forces found in the natural world.
Both are action-at-a-distance forces because their effects can be felt without direct contact.
Other types of fundamental forces include the strong nuclear force and the weak nuclear force.
Kepler’s Laws of Planetary Motion
Johannes Kepler described the motion of planets with three laws:
- First Law: Planets move around the Sun in elliptical, almost circular, orbits. The aphelion
Understanding Kinematics: Key Concepts and Forces
What does kinematics study? The movement of bodies.
Concepts Needed to Study the Movement of a Body
- Reference Frame: An oriented straight line in which motion occurs. It presents an origin and an axis.
- Position: The distance between the object and the origin of the reference frame.
- Displacement: The difference between any two positions.
When does a body move? When it varies its position with respect to the origin of the reference frame.
What is velocity? The measurement of the rate at which bodies move.
Read MoreUnderstanding Sound: Amplitude, Frequency, and Wave Behavior
Bigger Amplitude = More Energy. More Energy = Louder.
Sound dissipates (lessens) as it travels away from the source. This intensity can be measured. Intensity has units of watts/meter2 or the more commonly used decibels (dB).
Frequency = How fast the medium is vibrating. Measured in the number of waves per time period. More generally, frequency (or pitch) is measured in Hertz (Hz). Human ears can detect pitches from 20 Hz to 20,000 Hz.
Period is measured in seconds and is related to frequency: T =
Read MoreElectrical Line Clearance: Safety Distances & Grounding
Post Neutral Grounding
The neutral conductor of airline distribution networks of utilities will be connected to ground at the processing center or power generating plant. Also, in the distribution patterns TT and TN type, driver neutral and protection scheme for TN-S, must be grounded elsewhere, and at least once every 500 meters of line length.
General Conditions for Crossing Lines
1.2 Crossing Other AC Electrical Lines
When bare conductor lines are established on different supports, the distance between
Read MoreUnderstanding Forces and Motion: Dynamics Principles
Forces and Motion
Forces: They are interactions between bodies that can produce motion or deformation. Forces are measured with a dynamometer, and their SI unit is the newton (N). Forces can be contact forces, such as friction, or act remotely, such as weight. They are represented by vectors.
Identifying Forces in Motion
Whenever there is a change in the velocity vector (V), the object will be accelerated, and therefore, there is a resultant force. This occurs in the following cases:
- Movements with
Understanding Force, Weight, and Motion: A Physics Primer
Understanding Force, Weight, and Motion
Force is anything that can deform a body or change its state of rest or motion.
Force = mass × acceleration
Representation of Forces
Forces are represented by arrows. The line segments indicate the direction, and the pointed end of an arrow indicates the sense.
Types of Forces
- Instantaneous forces: Act only during a very short period (e.g., kicking a ball).
- Constant forces: Act on an ongoing basis (e.g., the Earth’s gravity).
The unit of force is the Newton (N) in
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