Notes, summaries, assignments, exams, and problems for Physics

1) What reason does Michael give for choosing the company where he works?

1. TD principles

Fundamentals of HVAC Duct Systems

• Pressure Measurement: Duct system pressure is measured in inches of water column (in. WC).
• Blower Function: The blower creates pressure to force air through the duct system, conditioning equipment, and into the room.
• Atmospheric Pressure: Standard atmospheric pressure is 14.696 psi.
• Manometer Usage: A manometer measures air velocity pressure in a duct.
• Airflow Measurement Tools: Anemometers or velometers are commonly used to measure airflow in air distribution systems.
• Airflow Check: Airflow can be checked by feeling it 2-3 feet from a register.
• Forced-Air vs. Natural-Draft: Forced-air systems use a blower, unlike natural-draft systems.
• Duct Pressure Components: Duct pressure equals velocity pressure plus static pressure.

Electricity

The smallest part in which matter can be divided is the atom. Its construction is like this:

Nucleus: protons - mass and positive charge / neutrons - mass and negative charge

Orbits of electrons: they do not have mass but they have negative electric charge

Electric charge is a property of subatomic particles which influences the action of forces between items.

Charges of the same sign repel each other / Charges of different signs attract each other

1 coulomb = 6.25x10^18 electrons / The atoms of an object can lose electrons and become charged / The atoms of an object can gain electrons and become charged / Electric current is the flow of electrons through a conductor material

An Electric Device

1) An electric device has a resistance of

Core Concepts of Motion & Force

Understanding Motion

Motion

Change in position relative to a reference point.

Frame of Reference

A system for specifying the precise location of objects in space and time.

Displacement

The change in position of an object. Always includes direction.

Speed

The distance traveled divided by the time interval during which the motion occurs.

Velocity

The speed of an object in a particular direction.

Acceleration

The rate at which velocity changes.

Forces and Their Effects

Force

Any action that can change the state of motion of an object.

Friction

An unbalanced force that acts against an object's direction of motion.

Static Friction

The force that resists the initiation of sliding motion between two surfaces that are in contact at

Physics Fundamentals: Multiple Choice Questions

1. The SI base unit for mass is:
e. kilogram

2. For which of the following situations is the conservation of mechanical energy most likely to be a valid assumption?
b. a parachutist falls from a plane

3. The slope of a line drawn tangent to a point on the curve of a position versus time graph describes what concept?
c. instantaneous velocity

4. As an object falls towards Earth:
d. the upward acceleration of Earth is negligible because of its large mass

5. Mass differs from weight in that:
b. weight is a force and mass is not

6. The main difference between kinetic energy and potential energy is that:
b. Kinetic energy involves motion, and potential energy involves position

7. A lead ball and a book are

Example 2: Find parametric equations for a particle that starts at (0, 3, 0) and moves around a circle as shown in Figure 17.1. The circle has a radius of 3 in the yz-plane, centered at the origin.

Solution: Since the motion is in the yz-plane, we have x = 0 at all times t. Looking at the yz-plane from the positive x-direction, we see motion around a circle of radius 3 in the clockwise direction. Thus, the parametric equations are:

• x = 0
• y = 3cos(t)
• z = -3sin(t)

Example 3: Describe in words the motion given parametrically by x = cos(t), y = sin(t), z = t.

Solution: The particle's x- and y-coordinates give circular motion in the xy-plane, while the z-coordinate increases steadily. Thus, the particle traces out a rising spiral, like a coiled spring.... Continue reading "Parametric Equations: Lines, Circles, and Motion in 3D Space" »

Vocab. 1

:

• go shopping
• hang out (penjar)
• listen to music
• play computer games
• read a magazine
• surf the net (navegar)
• watch sport on TV
• dull (avorrit)
• enjoyable (agradable)
• exciting
• frustrating
• interesting
• relaxing
• average (mitjana)
• correlation
• less than half (menys de la meitat)
• majority
• minority
• percentage
• survey (enquesta)

Vocab. 2

:

• adventure
• characters (personatges)
• context
• fantasy
• legend
• myth (mite)
• plot (trama)
• scene
• science fiction
• sript (guió)
• story
• tale (conte)
• angry
• comical
• courageous
• cowardly
• resourceful (ingeniós)
• sentimental
• spiteful (malèvol)
• genre
• metaphore
• moral
• setting (configuració)
• simile
• synopsis
• check over (revisar)
• come to
• come up with (presentar)
• work at
• go back to
• get across
• turn over (entregar)
• write down (apuntar-se)
• carefully
• completely
• convincingly
• daringly (atrevidament)

What is Matter?

Matter is the ‘element’ from which everything is made. It is any substance that has mass and takes up space by having volume.

Where Does Matter Come From?

A billionth of a second after the Big Bang, an important part of the symmetry of the universe was broken. Known as electroweak symmetry breaking, this was the moment when subatomic particles acquired mass for the first time.

What Processes Lead to the Creation of Matter?

A billionth of a second after the Big Bang, electroweak symmetry breaking occurred, and subatomic particles acquired mass for the first time. Among these particles were quarks. As the universe cooled, these quarks combined to form larger, more complex structures: protons and neutrons. Way before the universe... Continue reading "The Origin and Abundance of Matter in the Universe" »

Review

1 Balancing Moments

• seesaw: sube y baja 4
• Perpendicular: At a 90 degree angle to something
• Newton: The unit of measurement of force
• Clockwise: In the same direction as the movement of the hands on a clock
• Counterclockwise: In the opposite direction to the movement of the hands on a clock

Diagram

• a-You have to calculate the moment
• b-The wheel turns more easily when you spin it from near the rim. The distance

M=fd
F=30N
M=fd

Left is 2FI, same result
d=15cm
M=(30) (0.15)=4.5

Right is 2dF, same result
0.15m
M=4.5Nm

2 Making a Scale

• Spring constant: A measure of how stiff or strong a spring is
• Extension: The increase in the length of something
• Elastic: A material able to resume its original shape after being stretched or compressed
• Elastic Limit: The extent to