POE - Final Exam

What are the 6 steps of the EDP(Engineering Design Process)?

1. Define Problem

2. Generate Concepts

3. Develop a Solution

4. Construct and Test Prototype

5. Evaluate Solution

6. Present Solution

What are the 6 simple machines?

Inclined Plane, Wedge, Screw, Lever, Wheel and Axle, and Pulley

What is IMA(Ideal Mechanical Advantage)?

MA (Mechanical Advantage) without accounting for friction or anything that would cause the machine to lose energy

What is AMA(Actual Mechanical Advantage)?

MA(Mechanical Advantage) that takes into account all the energy losses in a machine

What is MA(Mechanical Advantage)?

Mechanical Advantage, assesses the performance of a machine

What is the IMA equation for a lever (the normal one)?

IMA = De/Dr

What is the AMA equation for a lever (the normal one)?

AMA = Fr/Fe

What is a 1st class lever?

When the fulcrum is between Fe and Fr

What are examples of 1st class levers?

Seesaw, Crowbar, Pliers, Scissors

What is a 2nd class lever?

When Fr is between fulcrum and Fe

What are example of 2nd class levers?

Wheelbarrow, Nutcracker, Oar, Bottle Opener

What is a 3rd class lever?

When Fe is between the fulcrum and Fr

What are examples of 3rd class levers?

Human arm, catapult, tweezers

What are the De and Dr in a wheel and axle system?

The radius of either the wheel or axle

What is a block and tackle pulley?

Pulley system with both fixed and movable pulleys

What is the IMA equation for Pulleys?

IMA = # of strands opposing the load

What is the IMA equation for inclined planes and wedges?

IMA = L/H

What is the IMA equation for Screws?

IMA = Circumfrence/Pitch

What is the equation for Pitch?

Pitch = 1 in/number of threads

What is the equation for moment?

Moment = F x D (perpendicular)

What is a gear?

A circular toothed object used to transfer rotary motion and torque through interlocking teeth

What is torque?

A twisting force that tends to cause rotation

What is a driver gear?

The gear that transmits the rotational motion of a motor or other device through the axle; the input gear

What is a driven gear?

The gear that is rotated by the energy transferred from the driver gear; output gear

What is a gear ratio?

A mathematical model that represents the behavior of a gear train

What is an idler gear?

A gear positioned between the driver an driven gear used to change rotational motion; makes input and output gear turn in the same direction

Do the driver and driven gear naturally turn in the same or opposite directions?

Opposite

What are the equations for the Gear Ratio?

GR/1 = Nout/Nin = Dout/Din = Win/Wout = Tout/Tin

What do N, D, W, and T stand for in the gear ratio?

Number of teeth, Diameter, Angular velocity (speed), and Torque

What is a gear train?

Is made up of two or more gears put together; used to transmit rotary motion and torque

What are the three main functions of a gear?

1. Change the speed of rotation

2. Change the direction of rotation

3. Change the amount of torque available to do work

What is true about the rpms of a larger and smaller gear?

The rpm of the larger gear is always slower/smaller than the rpm of a smaller gear

True or False: If two gears have the same axle their rotate at the same speed (rpm)

True

What is Resistance?

The opposition that a device or material offers to flow or direct current

What is friction?

The resistance the one surface or object encounters when moving over another

What is efficiency?

The ratio of useful energy output to the total energy input; the percentage of work input that is converted to work output

What is Current?

The movement of charged particles

What is Voltage?

The difference in electrical potential between two points

What is the equation for Electrical Power?

P = I x V, Electrical power = Electrical Current x Voltage

What are the equations for Efficiency?

Efficiency = Eout/Ein = Pout/Pin

What are the equations for Ohm's law?

V = I x R, I = V/R, R = V/I

What do V, I, and R stand for in the Ohm's law equations?

Voltage (Volts, V), Current(Amperes, A), Resistance(Ohms, symbol)

What is a series circuit?

A circuit where components are connected end-to-end; there is only a single path for current to flow

What is the equation for Rt in a series circuit?

Rt = R1 + R2 + R3….

What is a Parallel circuit?

A circuit where both end of components are connected together; there are multiple paths for current to flow

What is the equation for Rt in a Parallel circuit?

Rt = 1/(1/R1) + (1/R2) + (1/R3)….

What is Kirchoff's Law in terms of KVL?

Applicable to Series Circuit, Current is Constant, Voltage Drops, Vt = V1 + V2 + V3….

What is Kirchoff's Law in terms of KCL?

Applicable to Parallel Circuit, Voltage is Constant, Current Drops, It = I1 + I2 + I3….

What can a multimeter be used for?

To measure resistance, voltage, or current in an electrical circuit

What is a diode?

Something that allows current to flow only in one direction; it's schematic symbol is an arrow with a line next to it; longer wire is positive and shorter wire is negative

What is a resistor?

A an electronic component that resists the flow of electric current; measured in ohms, schematic symbol is a line with a zigzag section

What is fluid power?

The use of a fluid to transmit power form one location to another

What is hydraluics?

The use of a liquid flowing under pressure to transmit power form one location to another

What is the equation for MA in a hydraulic system?

MA = Fout/Fin

What is pneumatics?

The use of gasses/air flowing under pressure to transmit power form one location to another

What are the pros of fluid power?

1. Provides a lot of power

2. Easy to operate an control

3. One power source controls many operations

4. High power/low weight ratio

What are the key components of a hydraulic system?

1. Reservoir/reciever (stores fluid)

2. Fluid conductors (pipe or tube, allows for flow between components)

3. Pump/Compressor (converts mechanical power to fluid power)

4. Valve (controls the direction and amount of flow)

5. Actuators (Concerts fluid power to mechanical power)

What are the key components of a pneumatic system?

1. Drains

2. Regulators

3. Filters

4. Cylinders

5. Receiver Tank

6. Transmission lines

7. Valve

8. Compressor

What is one equation for power?

P = Q x P; Power = Flow Rate x Pressure

What is the equation for horsepower?

[flow (gpm) x pressure (psi)] / 1714 gpm/psi

What is 1 horsepower or hp equal to?

735.5 watts or 1714 gal/min x psi

What are the equations for Pascal's multiplication?

P1 = P2; F1/A1 = F2/A2

What are some key factors of rate of flow?

1. Determines actuator speed

2. Measured in gallons per minute or gpm

3. Generated by a pump

4. With a given flow rate, actuator volume displacement directly affects actuator speed

What is the equation for gpm?

(rpm x displacement) / 231

What is Pascal's law?

F = P x A; Force = Pressure x Area

What are the equations for Flow Rate?

1. Q = V/T; Flow Rate = Volume/Time

2. Q = V(A); Flow Rate - Flow Velocity x Area

What is Gay-Lussac's Law?

P1/T1 = P2/T2

What is Charles' Law?

V1/T1 = V2/T2

What is Boyle's Law?

P1V1=P2V2

What is the equation for Absolute temperature?

R or Rankine = F + 460

What is the equation for Absolute pressure

Given pressure + 14.7 lb/in^2

What is projectile motion?

Object that moves on both x and y axis and the same time

What are Vy1, Vy2, Vy, Ay, T and deltaY in terms of projectile motion?

Initial vertical velocity, final vertical velocity, average vertical velocity, vertical acceleration, time, and vertical displacement

What are Vx1, Vx2, Vx, Ax, T and deltaX in terms of projectile motion?

Initial horizontal velocity, final horizontal velocity, average horizontal velocity, horizontal acceleration, time, and horizontal displacement

What does Vi, g, x, and 0 stand for in the (Initial velocity, horizontal Displacement, Firing angle, and time of flight) with angle theta equation?

Initial velocity, gravitational acceleration, horizontal displacement, firing angle

What is Moment of Intertia (I)?

A mathematical property of a cross section (measured in inches^4) that gives important information about how that cross-sectional area is distributed about a centroidal axis. Also, it is the stiffness of an object related to it's shape orientation. A high I produces a greater resistance to deformation.

What is the equation for Moment of Intertia (I)?

I = (bh^3) / 12

What does Ixx mean?

Moment of Inertia in a joist or vertical position

What does Ix mean?

Moment of Inertia in a plank or horizontal position

What is Modulus of Elasticity (E)?

The ratio of the increment of some specified form of stress to the increment of some specified form of strain. Also known as the coefficient of elasticity, elasticity modulus. This defines the stiffness of an object related to the material's chemical properties A higher E produces a greater resistance to deformation and a lower delta max.

What is the equation for Modulus of Elasticity?

E = stress/strain

What side is stress and strain, respectively, projected on?

Strain = bottom

Stress = top

What is a Centroid?

Center of mass of an object or center of gravity (o) point or applied force caused by acceleration due to gravity. Object is in equilibrium if balanced along its centroid. It is determined by an object's line of symmetry.

What is a scalar quantity?

A quantity that is fully described by magnitude alone

What is a vector quantity?

A quantity that has both magnitude and direction

What is Sense?

The way in which a vector moves along a directional line

What are the trig functions relevant to force vectors?

1. Sin0 = Fy / F

2. Cos0 = Fx / F

3. Tan0 = Fy / Fx

What is a Resultant force?

The total amount of force acting on the object along with the direction of the combined force

What is Static testing?

Testing that seeks to find a material's response to constant loading

What is Dynamic testing?

Testing that seeks to determine a material's response to varying loading conditions (ex: magnitude, cycling, mode, etc)

What is a proportional limit?

The point where the linear part or the elastic range of the stress/strain curve ends

What is the Proportional constant

E = stress/strain; slope of linear part of curve

What is the Elastic limit?

Height of Elastic activity; where damage become permanent, a little higher than proportional limit

What is Resilience?

The area under the stress/strain curve, measures the amount of energy per unit volume that a material absorbs during the Elastic Range

What is the Yield Point?

When the elastic limit is exceeded; a small increase in stress = a much greater increase in strain

What is Offset Yield strength?

Defines the stress required to produce a tolerable amount of strain

What is Deformation?

Cross-sectional area decreases, load bearing abilities increase, strength increases

What is Plastic Deformation?

Unrecoverable elongation beyond elastic limit, when the load is removed only the elastic deformation will be recovered

What is tensile strength?

When load-bearing abilities peak, force required to continue
straining the test sample decreases, More necking

What is Failure?

Necking occurs until sample fractures