96 terms

Physical Science Equations / Formulas

Chapter 2 (Density) Chapter 3 (Pressure; Pascal's Principle; Gas Laws [Boyle's Law; Charles' Law; ***-Lussac's Law]) Chapter 4 (Moles/Molar Mass) Chapter 8 (Molarity) Chapter 9 (pH) Chapter 10 (Nuclear Decay) Chapter 11 (Speed or Velocity; Acce;eration) Chapter 12 (Newton's 2nd Law; Weight; Law of Universal Gravitation) Chapter 13 (Work; Power; Mechanical Advantage; Gravitational Potential Energy; Kinetic Energy; Efficiency) Chapter 14 (Temperature Conversions; Specific Heat) Chapter 15 (Wave Sp…
Density =
mass ÷ volume
Units for Density, mass and Volume
mass: grams or kilograms
volume: mL, L, or cm³
Density: g/mL, g/cm³, kg/L
Density Equation Rerarranged:
mass = Density × Volume
Volume = mass ÷ density
Pressure =
Force ÷ Area
Units for pressure, force, and area
force = Newton (N)
area = (meter)²
pressure = N / m² or pascal (Pa)
Pressure Equation Rearranged:
Force = Pressure x Area
Pascal's Principle:
If pressure is transmitted in a container with an enclosed fluid, the pressure increases at all points by the same amount. Small forces applied to a small area will produce a large force applied to a large area.
Applications of Pascal's Principle:
Hydraulic lifts for motor vehicles, brake systems in all motor vehicles.
Pascal's Principle Equation:
Pressure₁= Pressure₂
F₁/ A₁ = F₂/ A₂
Boyle's Law
For gases, the Pressure applied is inversely proportional to the Volume of a gas, as long as the temperature and amount of gas remains constant,
If pressure is increased then the volume will decrease; if pressure decreases then the volume of the gas will expand.
If you start with certain conditions of pressure and volume (P₁ & V₁) and change the conditions of pressure and volume (P₂ & V₂) then...
Boyle's Law Equation:
P₁x V₁= P₂x V₂
Boyle's Law Equation Rearranged:
P₂= (P₁x V₁) ÷ V₂ P₁= (P₂x V₂) ÷ V₁
V₂= (P₁x V₁) ÷ P₂ V₁= (P₂x V₂) ÷ P₁
Charles's Law
For gases, the Temperature applied is directlyproportional to the Volume of a gas, as long as the pressure and amount of gas remains constant,
If temperature is increased then the volume will increase; if temperature decreases then the volume of the gas will decrease as well.
If you start with certain conditions of temperature and volume (T₁ & V₁) and change the conditions of temperature and volume (T₂ & V₂) then...
Charles's Law Equation
V₁ ÷ T₁ = V₂ ÷ T₂
Charles's Law Equation Rearranged:
V₂= (V₁x T₂) ÷ T₁ V₁= (V₂x T₁) ÷ T₂
T₂= (V₂x T₁) ÷ V₁ T₂= (V₁x T₂) ÷ V₂
Gay-Lussac's Law
For gases, the Pressure applied is directly proportional to the Temperature of a gas, as long as the volume and amount of gas remains constant,
If temperature is increased then the pressure will increase; if temperature decreases then the pressure of the gas will also decrease.
If you start with certain conditions of pressure and volume (P₁ & T₁) and change the conditions of pressure and volume (P₂ & T₂) then...
Gay-Lussac's Law Equation
P₁ ÷ T₁ = P₂ ÷ T₂
Gay-Lussac's Law Equation Rearranged:
P₂= (P₁x T₂) ÷ T₁ P₁= (P₂x T₁) ÷ T₂
T₂= (P₂x T₁) ÷ P₁ T₂= (P₁x T₂) ÷ P₂
Moles → Mass
To convert from the moles of something to the mass (in grams) you need to multiply by the molar mass.
Molar Mass =
the mass (in grams) of one mole. For elements on the periodic table, the molar mass is equal to the atomic mass. Except that the units for atomic mass are a.m.u's (atomic mass units), whereas the units for molar mass are grams/mol.
Mass =
Moles x Molar Mass
Moles =
Mass ÷ Molar Mass
is the quantification of the concentration of a solution, expressed in terms of moles of solute (the substance that is dissolved) per liters of solution (volume of solute & solvent mixed together)
Molarity (M) =
moles Solute ÷ Liters Solution = mol / L
pH Values
pH is a term used to describe the relative strength of a acidic or basic solution
Acid Solutions -
have pH value between 0 and 7. The lower the pH number the stronger (more concentrated) the acid solution.
Basic Solutions -
have pH value between 8 and 14. The higher the pH number the stronger the base solution.
pH Equation =
- log [concentration of H+ ions]
pOH =
- log [concentration of OH- ions]
Nuclear Decay -
as a nucleus of an atom of an element disintegrates (decays) it discharges particles from the nucleus in order to become a more stable nucleus of an entirely different element.
Nuclear Decay Equation: Alpha Particle
Nuclear Decay Equation (Beta)
Speed or Velocity -
is equal to the distance travelled (usually in meters or kilometers) divided by the amount of time taken (usually in seconds or hours)
Speed Equation =
distance ÷ time
Units for Speed, distance and time
distance = meters or kilometers
time = seconds or hours
speed = meters / second (m/s) or kilometers / hour (km/hr)
Speed Equation Rearranged:
distance = speed x time
time = distance ÷ speed
Acceleration -
is the rate at which an object's speed / velocity changes. Acceleration can be positive (increase in velocity) or negative (decrese in velocity)
Acceleration Equation =
(Final Velocity - Starting Velocity) ÷ time
Units for Acceleration, velocity and time
velocity = meters / second
time = seconds
acceleration = meters / (second)²
Acceleration Equation Rearranged:
Final Velocity = (Acceleration x time) - Starting Velociy
Starting Velocity = (Acceleration x time) + Final Velociy
time = (Final Velocity - Starting Velocity) ÷ acceleration
Newton's 2nd Law of Motion
States that the acceleration of an object is directly proportional to the force that is applied to that object, and indirectly proportional to the object's mass
Newton's 2nd Law Equation =
Force = mass x acceleration
Units for force, mass and acceleration
Force = Newton (N) or kg x m/s²
mass = kilograms (kg)
acceleration = m/s²
Newton's 2nd Law Equation Rearranged:
mass = Force ÷ acceleration
acceleration = Force ÷ mass
Weight -
an object's weight is directly proportioal to its mass
an object's weight also depends on the acceleration due to gravity.
Acceleration due to Gravity (aka "g") depends on...
the mass of an object. Our solar system's star (our sun) has more mass than all of the planets combined, therefore it has more "g" than the planets. This is why the planets stay in orbit around the sun.
Earth's "g" =
9.8 m/s²
Weight Equation =
mass x "g"
Weight and Force are both measured in -
This is because both equations are measuring the force applied to an object.
In the force equation the acceleration is supplied by something other than gravity.
In the weight equation the acceleration is supplied solely by gravity.
Why does something on the Earth's Moon weigh less than that same thing does on Earth?
Because the Earth's Moon has less... "g"
Work -
the transfer of energy from one physical system to another expressed as the product of a force and the distance through which it moves a body in the direction of that force; "work equals force times distance".
If a force is applied, but the object does NOT move - then NO work is done
Work Equation:
Work = Force x distance
Units of work, force and distance
Force = Newtons
distance = meters
Work = Newton-Meters (N-m) or Joules (J)
Work Equation Rearranged:
Force = Work ÷ distance
distance = Work ÷ Force
(physics) the rate of doing work
Ex. measured in watts (= joules/second)
Power Equation =
Power = Work ÷ time
Units for power, work and time
work = Joules (J) or Newton-meters (N-m)
time = seconds
Power = Newton-meters / second or Joules / second or watts (w)
Power Equation Rearranged:
Work = Power x time
time = Work ÷ Power
Ideal Mechanical Advantage
a quantity that measures how much a simple machine multiplies force or distance (ignoring friction)
Ideal Mechanical Advantage =
Output Force ÷ Input Force or Resistance Force ÷ Effort Force
Output Force is
the weight of the object to be moved or the force exerted by a machine. Sometimes called the Resistance Force.
Input Force is
the amount of force used by the operator of a machine. Sometimes called the Effort Force.
Mechanical Advantage =
Input Distance ÷ Output Distance
Input Distance is
the distance that the operator has to move the object. Sometimes called the Effort Distance.
For a wheel and axle this is the distance that the wheel travels.
For an inclined plane this is the length of the ramp/inclined plane.
For a pully system this is the length of the rope used to pull up or let down a weight/resistance force/output force.
Output Distance is
the distance the output force is exerted through.
For inclined planes this is the vertical distance that the weight/resistance travels.
For a wheel and axle it is the distance travelled by the axle.
For a pulley system it is the vertical distance travelled by the weight/resistance force/output force.
Gravitational Potential Energy (G.P.E.)
energy stored by objects due to their position above Earth's surface; depends on the distance above Earth's surface and the object's mass
GPE Equation:
Gravitational Potential Energy = mass x height x acceleration due to gravity
GPE = m h g
Units for energy, mass, height and "g"
energy = Joules (J)
mass = kilograms (kg)
height = meters (m)
"g" (on Earth) = 9.8 m/s²
G P E Equation Rearranged:
mass = GPE ÷ (height x 9.8 m/s²)
height = GPE ÷ (mass x 9.8 m/s²)
"g" (if not on Earth) = PGE ÷ (mass x height)
Kinetic Energy (K.E.)
the energy an object has due to its motion
Kinetic Energy Equation:
KE = 1/2 (mass) x (velocity)²
Units for kinetic energy, mass and velocity
KE = Joules (J)
mass = kilograms (kg)
velocity = meters / second (m/s)
Kinetic Energy Equation Rearranged:
mass = 2KE ÷ v²
velocity = √2KE ÷ mass
Temperature Conversions -
there are three main temperature scales that are used by most high school science students:
Celsius Fahrenheit Kelvin
Celsius to Fahrenheit Conversion:
⁰F = 1.8 (⁰C) + 32⁰
Fahrenheit to Celsius Conversion:
⁰C = (⁰F - 32⁰) ÷ 1.8
Celsius to Kelvin Conversion:
K = ⁰C + 273
Kelvin to Ceksius Conversion:
⁰C = K - 273
Kelvin to Fahrenheit Conversion:
ºF = (K - 273) 1.8000 + 32.00
Fahrenheit to Kelvin
ºK = [(ºF - 32) ÷ 1.8] + 273.15
Specific Heat
The amount of heat that must be absorbed or lost for 1 kg of a substance to change its temperature by 1°K. Each substance has its own unique specific heat value.
Specific Heat Equation:
Energy (Q) = specific heat (c) x mass (kg) x change in temp. (∆ T)
Units for energy, specific heat, mass, and temperature
Energy = Joules
Specific Heat = Joules/kg x K
mass = kilograms
change in temperature = ⁰C or K
Specific Heat Equation Rearranged:
Specific Heat (c) = Energy ÷ (mass x ∆ T)
Mass = Energy ÷ (specific heat x ∆ T)
∆ T = Energy ÷ (specific heat x mass)
Wave Speed
The speed at which a wave travels through a medium (usually air or water). It is the product of wavelength and frequency.
Wave Speed Equation:
Wave Speed = frequency (ƒ) x wavelength (λ)
Units for wave speed, frequency and wavelength
Wave Speed = meters / second
frequency = 1/s (Hertz - Hz)
wavelength = meters
Wave Speed Equation Rearranged:
frequency = Wave Speed ÷ wavelength
wavelength = Wave Speed ÷ frequency
Ohm's Law
the law that states that resistance in an electrical circuit is equal to the voltage divided by current.
Ohm's Law Equation:
Resistance (R) = voltage (V) ÷ current (I)
Units for resistance, voltage and current
resistance = ohms (Ω)
voltage = volts (v)
current = amperes (A)
Ohm's Law Equation Rearranged:
Voltage = Resistance x Current
Current = Voltage ÷ Resistance
Electric Power -
rate at which electrical energy is converted into other forms of energy;
Electric Power Equation
Power (P) = current (I) x voltage (v)
Power (P) = I²•R = V ² / R = I•V
Units for power, current and voltage
Power = watts
Current = amps
Voltage = volts
Electric Power Equation Rearranged
I = P / V
V = P / I
R = P / I²