2.2 Statics Flashcards
Formula for Turning Moment
Moment (Nm) = Force (N) x Perpendicular Distance (m)
M = F x s
Formula for torque loading with extension
M1 = M2 x L1 / L2
* M1 = Torque setting
* M2 = Actual torque applied
* L1 = Length of wrench
* L2 = total extended length of wrench
Formula for Anti Clockwise Moment
M1 = F1 x S1
M1 = Total Anti-Clockwise movement
F1 = Force to the left of fulcrum
S1 = Lefthand distance from the fulcrum
Formula for Clockwise Moment
M2 = F2 x S2
M2 = Total Clockwise movement
F2 = Force to the Right of fulcrum
S2 = Right hand distance from the fulcrum
What is a Couple
A couple is a pair of forces that are equal in magnitude and opposite in direction applied at points separated by distances perpendicular to the forces. The combined moment of the forces produces a torque on the object they act on.
Couple Formula
Torque (T) = Force (N) x Distance (s) T = F x s
Torque (T) = Force (N) x Radius (r) x 2 T = Fr^2
Note that the factor of 2 in the second equation above is due to this being for a force couple.
For one force at a distance from the centre of rotation, this becomes a moment equation.
Calculation for Resultant forces
Resultant of two or more vectors that act in the same direction along the same line, add their values together. 300Nm + 300Nm = 600Nm
Resultant of two or more vectors that act in the Opposite direction along the same line, Take away the values from each other 300Nm - 300Nm = 0Nm
Triangle Method (Pythagoras’ Theorem)
a^2 + b^2 = c^2
What is a scaler Quantity
Scalar quantities have a magnitude but no direction. Some scalar quantities may have a direction, or undergo a change in direction, but they can be expressed by a numerical value regardless. Examples include length, distance and speed.
Distance, Volume, Area, Mass, Density, Length & Speed
Explain Vector Quantity
Vectors are usually represented in diagrams by arrows that point in the direction of an action. An arrow’s length represents the magnitude of the vector quantity.
Displacement, Force, Acceleration, Weight, Momentum, Moment & Velocity
Formula for Stress
Stress = Force (N) / Area (m^2)
Formula for Strain
Strain (-) = Change in Length (m) / Original Length (m)
Strain = /\L / Lo
Formula for Axial Stress
Axial Stress = Force / Cross sectional area.
S=F/A
Define Hook’s Law
Hooke’s law states that the extension of an elastic object is directly proportional to the force applied to it. F = k x e
Force (N) = k (Spring Constant N/m) x e (Extension (m)
Formula for Young’s Modulas
Youngs Modulas (E) = Stress/Strain
Formula for Pressure
Pressure (N/m2 or Pa) = Force (N) / Area (m^2)
or P=F/A
what are the 3 units of pressure
Bar, Millibar (mb) & Hectopascals (hPa)
Formula for Area
Area= Pi x r^2
What is the average Atmospheric Pressure
14.7 lb/in^2 Pounds per square inch (psi)
760 mmHg Millimetres of mercury
29.92 inHg Inches of mercury
1.01 bar Bar
101 325 Pa Pascal
1013.25 hPa Hectopascals
1013.25 mb Millibars
Formula for Absolute Pressure
Pabs = Pg+Patm
Absolute Pressure = Gauge Pressure + Atmospheric Pressure
Archimedes’ Principle states
That a body in a fluid will be subject to an upward force equal to the weight of fluid it displaces. This force is called the buoyant force.
What does the Bouyant Force equal
Weight of Fluid Displaced
Formula for Displacement Ratio
Ratio =P1/P2
P1 = Density of the Body (kg/m^3)
P2 = Density of Liquid (kg/m^3)
An object in uniform motion always has a ?
Constant speed
Formulas for Motion SUVAT
S = (u + v)t / 2 Distance (m)
S = ut +1/2at^2 Distance (m)
S = vt Distance (m)
h = ut +1/2gt^2 Distance (m)
v = u + at Final Velocity (m/s)
v2 = u2 + 2as Final Velocity (m/s)
a = v2 - u2 / 2s Acceleration (m/s2)