# Physics Formulas and Concepts for Pressure, Waves, and Electricity

Classified in Physics

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## Formulas to Calculate Pressure

P=pgh P=F/A Pabs=Pgauge+Patm P=Pa p=kg/m3 g=m/s2 h=m

### Newtons and Pascal

P=Pa Pa=N/m2 Pa in 1 atm 101,325Pa

### Archimedes Principle of Buoyancy

An object submerged in any fluid will experience a buoyant force equal to the weight of the fluid it has displaced.

### Pressure

Air pressure in the wheels of the car, buoyancy: (the force that makes objects float) the boat floats because the fluid is denser than the object.

### Buoyancy

Fw =m*g p=m/v Fb=Fa+Fw

### Waves

Regards to medium mechanical waves (need a medium), electromagnetic (can propagate in a vacuum), regards to propagation longitudinal (parallel to the direction of the propagation), transverse (perpendicular), circular (waves on water, circular fashion).

### Classify Sounds Waves

Lower frequencies infrasonic, highest ultrasonic (20Hz to 20KHz).

### Waves Phenomena

Reflection (the wave reflects on an object), refraction (the wave refracts on a medium and changes the speed; light, diffraction (the wave bends), resonance (when an original wave and the standing wave this occurs when the original wave adds to the reflected wave and creates a wave with a higher amplitude), interference (occurs when 2 different waves arrive at the same place at the same time and they add together, constructive, destructive).

### Sound Measured

We measure loudness of sound waves with a variable called sound pressure level (SPL) measured in decibels (dB). We can hear a sound depending on its frequency.

### Static Electricity

Is produced by friction (rubbing two objects), conduction (passing the electrons to one object to another), induction (force a bunch of electron accumulations).

### Electricity and Metals

Because of the electron sea, that's why metals are highly conductors of electricity.

### Ohm's Law

Voltage is equal to the amount of current by the resistance V=IR V=V I=A R=ohm.

### Kirchhoff's Junction Law

The amount of current entering into the circuit has to be equal to the one leaving. Drop law the rise has to be equal to the drop.

Watts.

R1*R2/R1+R2.

R1+R2+R3.

Concave, convex.