Physics is a discipline, which deals with matter, energy, and their interactions or in other words; it can be described as the study of matter and motion. This makes it a fundamental discipline and an important building block for thinking in the world.
Kinematics and Dynamics
Kinematics is the explanation of how objects move and dynamics is related with why objects move. These both are a branch of physics called mechanics. Galileo Galilei and Aristotle played a major role in establishing these disciplines.
Velocity and acceleration are both vector quantities and acceleration are directly related to velocity. Speed is the rate at which the position of an object changes over a given period, with no reference to direction, making it a scalar quantity. Velocity, on the other hand, is a vector involving both magnitude and direction, and usually includes crucial qualifying phrases like for Boston, or northward. Many people remain confused about what acceleration really is, but it can mean: an increase or decrease in speed without a change in direction, a reduction or upsurge of speed with a variation in direction; or a variation in direction with no alteration in speed. Therefore, if an object is moving in a rotational motion experiences acceleration even though its speed does not vary because its course will change incessantly.
Sometimes a hastening object will change its velocity by the same amount each second. This is referred to as constant acceleration. An object with constant acceleration can be confused with an object with a constant velocity, but if an object is changing its velocity by either a constant amount or a varying amount, it is termed as an accelerating object. An object with a constant velocity, on the other hand, is not accelerating. A free-falling object, for instance, usually accelerates as it falls. If observed it could average a velocity of 5m/s in the first second, 15m/s in the next second, 25m/s in the third second and 35m/s in the fourth approximately. Our object would constantly be accelerating.
Newton's first law of motion also called the law of inertia states; every body proceeds in its state of existence at rest or of moving consistently straight forward, apart from when it is forced to change its state forcibly. It basically means that if a body is not moving it will merely move when a force is applied to it, as well as an entity that is in motion will not alter its velocity until a net force acts upon it. Newton's second law states; the rate of alteration of the impetus of an object is relative to the resultant power acting on the form and is in a similar direction. It means that the force of the moving object will be equal to the opposing force.
i.e F = dP/dt.
Where F is the overall force, P is the momentum while t is the time passed. Where the objects mass m is constant, the equation becomes:
left-225961F= dP/dt = dmV/dt = mdV/dt = ma. So when a skydiver jumps from a plane and accelerates until he reaches the highest velocity possible, his acceleration is equal to nothing, this happens when air resistance is equal to the downward force of the skydiver.
Newton's third law states that: all forces occur in pairs, and the two forces are equal in magnitude and opposite direction. In simple terms, to evry action force there is an equal but opposite reaction force. A simple example is when one presses on a wall, an equal and opposite force acts back and is pushed at them.
Isaac Newton likened the speeding up of the moon to the speeding up of items on earth. This evaluation led to the deduction that the force of gravitational magnetism between the earth as well as other objects is contrariwise proportional to the distance separating the earths center from the objects center. The distance, though, wasn't the only variable affecting the magnitude of a gravitational force. Fnet = ma. Newton's law of universal gravitation encompasses gravity further than earth and is around the universality gravity has. Gravitational connections do not merely happen amongst the earth and other objects, and not basically amid the sun and other planets. Gravitational interactions occur amid all entities with an intensity that is unswervingly comparative to the product of their masses.
Fgrav = m1*m2/d2. So even as you seat in a physics classroom or lab, you are drawn to your laboratory partner, to the table you are at work on and even your book. These laws are widely accepted theory and they guide scientists in their study of planetary orbits.
Kinetic energy is the power held by an object in motion while potential energy is the energy an entity has because of its location relative to some other object. Example when you stand on top of a stairwell you have more potential energy than when you are the bottom because the earth can pull you down through the force of gravity. Also when you hold two magnets separately, they have additional potential energy than the time they are adjacent to each other. If you allow them to go, they will move in the direction of each other doing work in the process. A tennis player also applies these forces when his kinetically energized swing releases potential energy that is in a tennis racket then moves it to the ball. The electricity that fuels our homes is provided by potential energy turned kinetic either in the form of a hydroelectric dam or an electric plant fueled by coal.
A projectile is an object upon which the force acting is gravity. For example, an object dropped from rest or an object thrown vertically upwards or an object thrown upwards at an angle to the horizontal. Therefore, a projectile is any object that once projected or dropped continues in motion by its own inertia and is influenced by the downward force of gravity. Projectile motion is used in ballistics that is the study of gunfire patterns for the purpose of crime solving. It is also applied to curve balls, dimpled golf balls and other tricks with spin, to make them travel much farther.
Circular motion is the movement of an object laterally on the perimeter of a circle or rotation along a round path. It can be even with the constant angular rate of turning and continuous speed, or not-uniform, with constant angular rate of rotation. An example of circular motions includes an artificial satellite orbiting the earth at a constant height, a stone that is tied to a rope and is being swung in circles or a car turning over a bend in a race truck. Another application is the rotating fluid. Every time we make a cup of tea, as we stir the liquid the center forms a dip in the center, the surface being defined by how the centripetal acceleration changes with radius; and we are reminded that rotating fluids do not have a flat surface. Circular motion is also used in centrifugal casting to produce fine-grained castings. It is also useful for solving problems dealing with non-uniform circular motion.
Momentum and Impulse
An object has momentum if it possesses velocity. Momentum is found by multiplying the mass and the velocity of the object together. Impulse is directly related to momentum because the impulse is a term describing an objects change in momentum. If an object varies its speed, then its momentum varies. The measurable quantity of momentum changing is the objects impulse. So for the momentum of an object to change, a force must be applied for a given period. If a small force is employed in a long period, the change in momentum can be quite large, and if a large force is exerted over a small period, a large change in momentum can occur. For example in baseball, when a ball is struck with only a small part of the baseball bat, it is not in contact with it for a long period so the change in momentum or impulse is minimal and, therefore, the ball does not travel very far. The reverse where the bat hits the ball squarely results to more contact, i.e.; the force gets exerted for a longer period resulting in a greater change in momentum or impulse. Car airbags are designed based on momentum and impulse principles, such that when a driver gets into an accident and their momentum carries them forward into the steering wheel, through the airbag a smaller force is exerted over a long period to change the momentum of the driver to stop. Deprived of the airbag, a great force is utilized for a short time causing more damage to the driver. Another example is when the brakes of a car traveling down the road are lightly tapped, the strength of the brakes is applied over a small time ensuing in a minor impulse thus a small change in the cars momentum.
A wave is a disturbance that travels through a medium from one place to another. Waves are almost everywhere. A wave is fairly a different entity than a particle. For example, a baseball thrown through a window transfers energy from one point to another but it involves the movement a material object between two points while a water wave carries energy as it causes erosion on the shore, but the material is not continuously being transferred onto the shore. Most of the information we receive are in the form of waves, including from TVs and music. Waves handover energy in diverse forms; some are proving very useful and others deadly. Animals use wave motions to propel themselves through their surroundings and habitats. When it comes to waves with destructive properties, tsunamis or tidal wave is a very large water wave that is produced by seismic phenomena. It can move up to speeds of 500km/h and have a period of 60 minutes, and moves across the ocean quickly causing much damage to coastal regions. In this case, properties like speed and amplitude are an important examination.Shock waves created by lighting or aircraft flying at speeds greater than the speed of sound in air can cause sonic booms. Acoustic engineers can make soundproof obstructions or rooms since sound waves cannot travel in a vacuum. Sound waves also travel relatively slower than light waves, which helps our brain to enable us to locate the source of the sound. It is a measurable difference in the time it takes he sound waves to reach both ears. Sound waves are also useful in detecting objects underwater using sonar, based on acoustic echo. High frequency or ultrasonic sound waves have been used to clean jewelry and teeth, and also to help animals communicate or physicians make observations of internal organs.
Transverse Wave and Longitudinal Waves
A transverse wave is an up and down wave that looks like a water wave. It is called his because the motion of particles in the wave medium is perpendicular to the waves direction. These include the waves you can make on a jump rope, on a guitar string or electromagnetic waves like visible light and X-rays or waves created by audiences in football games. Sometimes the wave medium oscillates parallel o parallel to the waves direction. In this case, it is called a longitudinal wave. Example if a long slinky is stretched out across a table top with one end fixed, and the other end is a applied a quick push-pull motion, the push would cause a compression that would travel down to the other end. That is what a longitudinal wave looks like. Longitudinal waves do not possess crests or troughs. For example eels and snakes use transverse waves to push against water or ground for movement. Earthworms, on the other hand, use longitudinal waves for movement or propulsion. One-celled animals use flagella in a whiplike wave motion to move about.
The Doppler effect is the change in frequency of a wave for an observer moving relative to its source. It is commonly heard when a vehicle is sounding an alarm or horn approaches, passes, and then regresses fro...
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