physicsforbeginners-blog

[physicsforbeginners-blog]

Wave Interference

Waves do not need to cancel out in order to be considered destructive interference. Simply their amplitude directions must be in opposing ways.  

After interference occurs, the "components" of the formed wave return back to their original amplitudes and continue along the medium to their destination. So if a crest with an amplitude of 1 interferes with a trough that has an amplitude of -1, they cancel out due to destructive interference. But after interference is complete, it will become a crest of 1 displacement and a trough of -1 displacement continuing in their motion. (Displacement is amplitude.)

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Wave Refraction - Part 2

In the picture, the red colored rays represent incident rays, the blue colored rays represent refracted rays, and the green colored rays represent reflected rays. 

Waves can experience multiple phenomenons at once, not just reflection for a period of time and then another. 

To clarify, the critical angle is the maximum degree of refraction that can occur. That's why we're using the critical angle to find out at what incident angles will waves total internally reflect, which of course solely depends on the properties of the two mediums. Think of the critical angle as a sort of limit or indicator of measurement. Any degree below the critical angle includes the phenomenon of refraction, but any degree above the critical angle only results in total reflection. It is different from the incident angle, because the incident angle is formed by the incident ray, but the critical angle is specified as the angle of incidence that causes a 90° angle of refraction. The incident angle is what actually happens in reality, the critical angle is mainly a ideal tool used to calculate the angles of incidence in which waves will totally reflect. That does not mean the angle of incidence will never cause a 90° angle of refraction.

[physicsforbeginners-blog]

Wave Refraction - Part 1

Index of refraction is also called refractive index. The medium is a substance the waves travel through. The medium's properties influence the velocity of the wave. 

To be precise, the speed of light in a vacuum is 2.99792458 • 10^8 m/s, or light travels 299,792,458 meters per second. It usually is rounded off to 3 • 10^8 m/s. If you would prefer to be more accurate in your calculations, feel free to include however much significant digits you like, such as 2.998 • 10^8 m/s. 

[physicsforbeginners-blog]

Wave Reflection

Theta (θ) is a Greek letter commonly used to represent geometric angles.

Objects can both specularly and diffusely reflect at the same time. Take a metal cup, for instance. It somewhat specularly reflects, because you can see your curved image on it, but it's all in the color of the metal. But the metal cup also diffusely reflects, because you see the metal cup itself. 

[physicsforbeginners-blog]

Wave Characteristics

The wavelength is represented by Greek letter lambda λ. Hertz (Hz) is equal to a cycle per second. The velocity of the wave would equal v = λf, where velocity equals wavelength times frequency. If you remember the equation v = d/t, wavelength would be the distance and period would be the time in this case. But you know the period is equal to 1/f, so v = λ/ 1/f equals v = λ/f. Dividing by a fraction is equal to multiplying the reciprocal. 

Essentially, a transverse wave moves perpendicularly to the medium it is traveling in. That means it moves at 90° angles (amplitude to resting position), and so it moves up and down. Longitudinal waves move left and right, which means their direction of propagation is parallel to the medium it is traveling in. In a sound wave, which is a longitudinal wave, it affects the pressure of the particles in the air. So the point of highest pressure is the crest, and point of lowest pressure is the trough.

[physicsforbeginners-blog]

Gravity (Part 1 - Calculation)

The 4 fundamental forces of nature are: gravitational force, electromagnetic force, strong nuclear force, and weak nuclear force.

[physicsforbeginners-blog]

Gravity (Part 1 - Theory)

The 4 fundamental forces of nature are: gravitational force, electromagnetic force, strong nuclear force, and weak nuclear force. 

This is the gravitational force that applies to the whole universe. However, Newton's classical gravity does not apply to very, very strong gravitational forces, which is where Einstein's General Theory of Relativity comes in. Gravity is the weakest of the 4 fundamental forces. 

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Spring Force

A contact force is a force that occurs at points of contact between two or more objects. Contact forces includes: normal force, frictional force, tension force, air resistance force, applied force, and spring force.

The spring force is the force exerted by a stretched/compressed spring upon the applied force acting on it.

The spring constant depends on the material and shape of the spring.

[physicsforbeginners-blog]

I need Feminism because being a female Physics student shouldn’t be frowned upon.

I’ve been told its shocking for a girl to be able to understand physics let alone be allowed to study a degree in it!

[physicsforbeginners-blog]

Applied Force

A contact force is a force that occurs at points of contact between two or more objects. Contact forces includes: normal force, frictional force, tension force, air resistance force, applied force, and spring force.

The applied force is a force applied on an object by a person or another object. It often causes an object to be set in motion or to stop its motion.

[physicsforbeginners-blog]

Air Resistance Force

A contact force is a force that occurs at points of contact between two or more objects. Contact forces includes: normal force, frictional force, tension force, air resistance force, applied force, and spring force.

The air resistance force is the frictional force acting upon objects that are in the air. The amount of air resistance depends on many factors, most commonly the speed and the surface area of the object being acted upon.  In other words, the more speed/surface area object has, the more force air resistance is applying on.

Note that since it's a frictional force, it acts in the direct opposite of an object's motion. 

[physicsforbeginners-blog]

Tension Force (Part 2)

A contact force is a force that occurs at points of contact between two or more objects. Contact forces includes: normal force, frictional force, tension force, air resistance force, applied force, and spring force.

The tension force is the pulling force transmitted through a string, rope, cable, or wire when pulled tight by forces acting on opposite ends. It is directed along the length of the wire and pulls equally on the objects on the opposite ends of the wire. (or any other similar objects)

[physicsforbeginners-blog]

Tension Force (Part 1)

A contact force is a force that occurs at points of contact between two or more objects. Contact forces includes: normal force, frictional force, tension force, air resistance force, applied force, and spring force.

The tension force is the pulling force transmitted through a string, rope, cable, or wire when pulled tight by forces acting on opposite ends. It is directed along the length of the wire and pulls equally on the objects on the opposite ends of the wire. (or any other similar objects)

In the right triangle, the angle 48° is between the Tsub1 (black line) and the x-component (red line). Similarly, in the left triangle, the angle 44° is between the Tsub2 (black line) and the x-component (red line).

[physicsforbeginners-blog]

Frictional Force

A contact force is a force that occurs at points of contact between two or more objects. Contact forces includes: normal force, frictional force, tension force, air resistance force, applied force, and spring force.

The frictional force is the force exerted by a surface upon the object to attempt to disable the object from moving across the surface.

Greek letter mu (μ) represents the coefficient of friction, which is the ratio of the magnitude of the friction force divided by the magnitude of the normal force. It is used to find out how much resistance to motion exists between the two surfaces. Higher the number, the higher the frictional force. It depends on the materials of the surface. 

Without friction, we will be slipping everywhere... 

[physicsforbeginners-blog]

Normal Force

A contact force is a force that occurs at points of contact between two or more objects. Contact forces includes: normal force, frictional force, tension force, air resistance force, applied force, and spring force.

If the object is at rest, then the force of gravity, the normal force, and all other forces cancel out. 

[physicsforbeginners-blog]

Newton's Third Law of Motion

For every action, there is an equal and opposite reaction.

If the bookshelf wasn't pushing at you, then you will feel no pressure at all. 

[physicsforbeginners-blog]

Newton's Second Law of Motion

The acceleration of an object produced by a net force varies directly with the magnitude of the net force, and varies inversely with the mass of the object. Thus F= ma. (Net force = mass times acceleration, force measured in newtons, mass measured in kilograms, and acceleration measured in meters per second per second)

1 Newton = 1 kg • m/s²