TEST 2 USEFUL FORMULAS – Physics 131

Vocabulary flashcards based on useful formulas and concepts in Physics 131.

Density

Mass per unit volume.

Slope

The ratio of the change in y to the change in x, given by $rac{y_2 - y_1}{x_2 - x_1}$.

Equation of a straight line

Described by the formula $Y = mX + b$, where m is the slope and b is the y-intercept.

Area of a rectangle

Calculated as Length multiplied by Width.

Area of a circle

Given by the formula $ext{Area} = <br /> u imes r^2$.

Volume of a rectangular box

Calculated as Length multiplied by Width multiplied by Height, or LWH.

Volume of a sphere

Given by $rac{4}{3} <br /> u imes r^3$.

Volume of a cylinder

Calculated as $<br /> u imes r^2 imes h$.

Distance

The length of the path traveled.

Speed

Defined as ext{Speed} = rac{Distance}{Time}.

Displacement

Change in position, calculated as $X_f - X_i$.

Velocity

Defined as ext{Velocity} = rac{Displacement}{Time}.

Equation of motion for final velocity

Expressed as $v = v_0 + at$.

Equation of motion for distance

Written as d = v_0 t + rac{1}{2} a t^2.

Pythagorean theorem

States that $r^2 = x^2 + y^2$.

Sine of an angle

Defined as ext{Sin}( heta) = rac{Opposite ext{ side}}{Hypotenuse}.

Cosine of an angle

Defined as ext{Cos}( heta) = rac{Adjacent ext{ side}}{Hypotenuse}.

Tangent of an angle

Defined as ext{Tan}( heta) = rac{Opposite ext{ side}}{Adjacent ext{ side}}.

Force

Given by Newton's second law as $F = ma$.

Weight

The force of gravity acting on an object, calculated as mass multiplied by acceleration due to gravity.

Friction

Calculated as $F = <br /> u N$, where N is the normal force.

Momentum

Defined as mass multiplied by velocity, or $p = mv$.

Change in momentum

Calculated as $ext{Δ}p = ext{Final momentum} - ext{Initial momentum}$.

Total momentum

The principle that Total Momentum before equals Total Momentum after.

Torque

Given by $au = Fd ext{Sin}( heta)$.

Work done

Calculated as $Work = FdCos( heta)$.

Kinetic Energy

Calculated as KE = rac{1}{2} mv^2.

Potential Energy

Given by $PE = mgh$.

Power

Defined as ext{Power} = rac{Work}{Time}.

Mechanical Efficiency

Defined as $rac{Work ext{ output}}{Work ext{ input}}$.

Percent Error

Calculated as rac{|A_1 - E_1|}{A_1} imes 100 ext{%}.

Percent Difference

Calculated as rac{|E_1 - E_2|}{rac{E_1 + E_2}{2}} imes 100 ext{%}.

Stress

Defined as Force divided by Area.

Strain

Calculated as $rac{ ext{Change in Length} ext{ (ΔL)}}{L_0}$.

Young's Modulus

Defined as $rac{Tensile Stress}{Tensile Strain}$.

Pressure

Defined as Force divided by Area.

Pressure in a liquid

Given by $P = <br /> ho g h$.

Absolute Pressure

Calculated as Atmospheric pressure plus $<br /> ho g h$.