Ch.5 Physics (Important Ch notes)

Question 1

The higher the mass of something, the more the weight of it is

Question 2

The difference between Mass and Weight:

Answer 2

The mass is the amount of matter in an object.
The weight is the pull of gravity on an object.

Question 3

What are the 3 states of matter:

Answer 3

Solid, Liquid and Gas

Question 4

Anything w/ matter has mass and volume

Question 5

Specific Gravity tells you whether something is floating or sinking in water (An object above 1 will sink in water)

Question 6

The same formulas used for Specific Gravity are used to find the Density of gases by substituting air or hydrogen for water

Question 7

What are the 3 types of friction:

Answer 7

Static friction, Sliding friction, Rolling friction

Question 8

5 ways in how simple machines are used:

Answer 8

1. To transfer energy like in a generator transforming mechanical energy in electrical energy
2. To transfer energy from one place to another like connecting rods, crankshaft, and reduction gears to transfer energy from an aircraft engine to its propeller
3. To multiply force, a system of pulleys used to lift a heavy load
4. To multiply speed, like a bicycle by which speed can be gained by a greater force
5. To change the direction of a force, like a flag hoist, a downward force on one side of the rope exerts an upward force on the other side, raising the flag toward the top of the pole

Question 9

What are the 6 types of Simple Machines:

Answer 9

The Lever
The Pulley
The Wheel and Axel
The Inclined Plane
The Screw
The Gear

Question 10

The wheels in pulleys are sometimes referred as the “Sheave” or the “Sheaf”

Question 11

The frame that supports the wheel in a pulley is called a “Block”

Question 12

With Gears, the one with the input force is called the “Drive Gear” and the other one is called the “Driven Gear”

Question 13

Bolts, Screws and Wedges are examples of devices that operate on the principle of the Inclined plane

Question 14

What are the 5 types of Stress

Answer 14

Shear
Tension
Bending
Compression
Torsion

Question 15

The difference between Speed and Velocity

Answer 15

Speed refers to how fast an object is moving or how far the object will travel in a specific time.

Velocity tells the speed and direction of an object.

Question 16

Load is same as Resistance

Question 17

Work is described as a force acting through a distance

Question 18

Potential Energy is classified in 3 groups

Answer 18

1. Energy due to position
2. Energy due to distortion of an elastic body
3. Energy which produces work through chemical action

Question 19

Fulcrum is where things can balance, move, pivot

Question 20

The difference between Gas and Liquid

Answer 20

Gas can be compressed and liquid can’t

Question 21

Newtons 1st Law

Answer 21

An object at rest remains at rest, an object in motions remains in motion at constant speed.

Also known as Inertia

Example: When an airplane is brought to a sudden halt in the parking area and the passengers are thrown forward in their seats

Question 22

Newtons 2nd Law

Answer 22

A body that has great momentum (motion) has a strong tendency to remain in motion and is therefore hard to stop

Example: A train moving at a low velocity is difficult to stop because of its large mass

Question 23

Newtons 3rd Law

Answer 23

For every action there is an equal and opposite reaction

Example: When you jump, your legs apply a force to ground and the ground applies an equal and opposite reaction force that propels you into the air

Question 24

Heat may also be defined as the total kinetic energy of the molecules of any substance

Question 24

Energies that can be converted into heat energy:

Answer 24

Mechanical Energy Electrical Energy Chemical Energy Radiant Energy Nuclear Energy Sun

Question 25

The hotter the body the more kinetic energy is possessed, the cooler the less

Question 26

3 ways heat can be transferred:

Answer 26

Convection Conduction Radiation

Question 26

Water has a high heat capacity

Question 27

Solids will expand when heated and contract when cooled, as in the atoms will separate and connect

Question 28

Sound travels faster through water than it does through air at the same temp

Question 29

Engine power output is calculated on dry air

Question 29

The 4 forces of flight: (All measured in lbs)

Answer 29

Lift Weight Thrust Drag

Question 30

As the boundary layer approaches the center of the wing, it begins to lose speed due to skin friction and it becomes thicker and turbulent. Here it is called the turbulent layer. The point at which the boundary layer changes from laminar to turbulent is called the transition point. Where the boundary layer becomes turbulent, drag due to skin friction is relatively high. As speed increases, the transition point tends to move forward. As the angle of attack increases, the transition point also tends to move forward. With higher angles of attack and further thickening of the boundary layer, the turbulence becomes so great the air breaks away from the surface of the wing. At this point, the lift of the wing is destroyed and a condition known as a stall has occurred

Answer 30

Example on page 198 for figure 5-58

Question 31

The center of gravity is also referred to as the center of rotation.

Question 32

5 Types of Aircraft stability:

Answer 32

Static Stability Dynamic Stability Longitudinal Stability Lateral Stability Directional Stability

Question 33

4 Types of Tabs

Answer 33

Trim tabs Anti-servo tab Balance tab Servo tab

Question 34

To give the wing the ability to produce maximum low speed lift without being drag prohibitive, retractable high lift devices, such as flaps and slats, are utilized.

Question 35

Transonic flight is the most difficult flight regime for an airplane, because part of the wing is experiencing subsonic airflow and part is experiencing supersonic airflow

Question 36

Helicopter Aerodynamics - The helicopter, as we know it today, falls under the classification known as rotorcraft. Rotorcraft is also known as rotary wing aircraft, because instead of their wing being fixed like it is on an airplane, the wing rotates. The rotating wing of a rotorcraft can be thought of as a lift producing device, like the wing of an airplane, or as a thrust producing device, like the propeller on a piston engine.

Question 37

For a subsonic airfoil, the aerodynamic center, or the point of support, is approximately 25 percent of the way back from the wing leading edge. In supersonic flight, the aerodynamic center moves back to 50 percent of the wing’s chord, causing some significant changes in the airplane’s control and stability

Question 38

What's the specific heat of water?

Answer 38

1.000

Question 45

What's the specific heat of mercury?

Answer 45

0.033

Question 46

Types of Density Altitude:

Answer 46

Indicated Altitude True Altitude Absolute Altitude Pressure Altitude Density Altitude

Question 47

The 4 forces of flight:

Answer 47

1. When an airplane is accelerating, it has more thrust than drag 2. When an airplane is decelerating, it has less thrust than drag 3. When an airplane is climbing, it has more lift than weight 4. When an airplane is at constant altitude, loft and weight are equal

Question 48

Stall can happen at any speed

Question 49

The center of gravity is in front of the center of lift because you want the aircraft to be able to pitch down

Question 50

Shifting Ailerons allow control over roll in lateral stability

Question 51

Standard temperature at sea level:

Answer 51

15 degrees celsius

Question 52

Press altitude is corrected for non standard temperature variations

Answer 52

(Cool air is more dense than warm air, so pressure over an area of cool air is higher than an area of warmer air. Pressure changes throughout the day as temperatures increase and decrease, so it's important to periodically update the altimeter setting in an aircraft to make sure the altitude shown is accurate.)

Question 52

Temperature lapse rate:

Answer 52

2 degrees celsius per 1,000 feet

Question 52

Heat, humidity and altitude affect density altitude

Question 53

The higher the density altitude, the better the aircraft performance. The lower the DA, then the weaker the performance Example of Density Altitude can be found on project 05 on procedure 2

Question 53

Pressure is typically measured in psi, but other units include inches or millimeters of mercury and millibars

Question 54

Static is how fast the aircraft takes to recover

Question 55

Why does increasing the temp of a gas decrease its density ?

Answer 55

The volume increases, so there's ;less mass per unit volume

Question 56

Water vapor is less dense than air

Question 57

Differential pressure is the difference between pressures being read at 2 different locations

Question 58

An airplane will have to fly the fastest to produce the required lift under which atmospheric conditions?

Answer 58

High Temp and High Humiditiy

Question 59

Relative Humidity is expressed as a percentage and is based on what?

Answer 59

The prevailing air temp and pressure

Question 60

An atmosphere with 20% water vapor will weight the most

Answer 60

(Less water vapor will cause more weight but more water vapor will weight less)

Question 61

An atmosphere with 20% water vapor will weight the most

Answer 61

(Less water vapor will cause more weight but more water vapor will weight less)

Question 62

If the pressure on a confined liquid is doubled then the volume will remain the same

Question 63

What happens when a fluid flows theough a convergent shape (consider subsonic speed)

Answer 63

The velocity of that fluid will increase and the pressure will decrease

Question 64

What happens when a fluid flows theough a divergent shape (consider subsonic speed)

Answer 64

The velocity will decrease and the pressure will increase