NUMS exam 1 Flashcards
He prefers death _________ dishonor.
1) Over
2) On
3) Upon
4) To
To
what does the word spill mean?
spread over
Na+ (sodium ions) are nearly __________ times greater in fluid outside the cell than inside
10x
- concentration of Na+ ions is approximately 10 times greater in fluids outside (extracellular) the cell compared to inside (intracellular) the cell
- creates difference in ion concentration and helps resting membrane potential and other important factors
question could have been worded better but means concentration of Na+ not the actual fluid count maybe
Oxytocin’s role in childbirth
Induces labor pains
- plays crucial role in initiating and regulating uterine contractions during labor
oxytocin = “love hormone”
ADH (antidiuretic hormone)
released in response to increased blood osmolality or decreased water content
- helps body retain water by reducing urine production and increasing water reabsorption in the kidneys
where are neurotransmitters synthesized and stored?
within the presynaptic neuron, specifically in structures called synaptic vesicles
- When an action potential reaches the presynaptic neuron, these vesicles release neurotransmitters into the synapse.
endorphins are produced in ______
within the various parts of the brain, including the hypothalamus and pituitary gland
endorphins = natural painkillers and mood elevators
adrenal glands
located on top of the kidney and produce hormones to regulate metabolism, immune system, blood pressure, and response to stress
Leydig Cells
located in the testes
responsible for production and secretion of testosterone, primary male sex hormone
spermatogenesis & oogenesis
spermatogenesis: formation of sperm, is continuous and prolific (producing a lot)
- hundreds of millions of sperm are produced per day; each sperm takes about 7 weeks to develop
oogenesis: development of a mature egg, is a prolonged process
- immature eggs form in the female embryo but do not complete their development until years or decades later
FSH & LH
FSH (follicle-stimulating hormone): tells ovaries in females and testes in males to start making cells for reproduction, signal that starts engine
- one of the hormones released by the pituitary gland in response to GnRH
- stimulates Sertoli cells
LH (luteinizing hormone): helps regulate menstrual cycle in females and stimulates the testes to produce testosterone in males, supervisor that oversees the work and makes sure everything is going smoothly
Sertoli & Leydig cells
Sertoli cells: cells found in testes of males, provide support & nourishment for developing sperm cells - construction workers who build & maintain the structures needed for making sperm
- secrete hormone inhibin
- stimulated by FSH
Leydig cells: also in testes of males (located between seminiferous tubules), produce testosterone & other androgens (male hormones)
- stimulated by LH
The estrogen hormone secretion during oogenesis is stimulated by:
FSH (follicle stimulating hormone)
- FSH responsible for stimulating growth and development of ovarian follicles in the ovaries
Which of the following hormones of the pituitary gland regulate the menstrual cycle?
FSH and LH
- both produced by anterior pituitary gland
Which of the following traits is transmitted directly from an affected father to only his son?
Y-linked traits
- Y linked traits are passed from father to son through the Y chromosome. not present on the X chromosome and are specific to male inheritance
When both the alleles of a gene pair are same, the organism is said to be:
Homozygous
- means having 2 identical pairs of a gene, whether both dominant or both recessive
Endosymbiotic Theory
Mitochondria and chloroplasts were once free-living organisms that were engulfed by ancestral eukaryotic cells
Analogous & Homologous Organs
Analogous Organs: similar in function but different in structure
- these organs have evolved independently in different species to perform similar functions in response to similar environmental pressures, even though their internal structures are distinct
Homologous Organs: similar structures but different functions
- due to shared ancestry
- think homo doesnt function well
Function of antibodies (3 primary functions)
**Antibodies (also called Immunoglobulins): proteins that protect from antigens = toxin or foreign substance that induces immune response
Primarily work by:
1. Neutralizing antigens (attach to antigens changing their chemical composition)
- Precipitating antigens (two soluble proteins come together to make an insoluble protein, creating precipitate)
- Enhancing phagocytosis (ingest and eliminate)
Cytokines
small proteins that are crucial in managing growth and activity of other immune system cells
- cannot get into cell itself because of size so interact with cytokine receptors at surface of cell
Pepsinogen is converted into its active form pepsin by:
Hydrochloric Acid (HCl)
- Pepsinogen is the inactive form thats produced in stomach lining by chief cells
- Once comes into contact with HCl, turns into active form pepsin that breaks down food
Intrinsic Factor
- protein that helps your intestines absorb Vitamin B12
secreted by stomach
Lymphocytes
- specific type of white blood cell
- one of body’s main types of immune cells
- made in bone marrow and found in the blood and lymph tissue
where does digestion of each of these foods start in the body:
carbohydrates
proteins
fats
vitamins
carbs: oral cavity (mouth), saliva breaks down food
proteins: stomach, pepsin breaks down protein molecules
fats: small intestine, while some small digestion happens in the stomach, main digestion happens in the small intestine with the help of bile
vitamins: not digested because already in simplest form, so they are absorbed instead
Describe the 4 types:
Natural/Acquired (artificial) passive/active immunity
Passive Immunity: involves transfer of antibodies from one person to another, immediate but short-term protection
- Acquired (artificial) passive: medical intervention such as antibodies injected for snake bite, gives protection but doesnt last long because body did not make it itself
- Natural passive: occurs naturally, like mother passing antibodies to a baby
Active Immunity: body’s own response to a pathogen, long-term protection
- Acquired (artificial) active: medical intervention such as vaccine where weakened form of pathogen is injected
- Natural Active: happens naturally when body fights off a virus and remembers it
vaccination is an example of what type of immunity
acquired/artificial active immune
The heart chamber from where aorta originates:
Left ventricle
- left ventricle pumps oxygenated blood into the aorta, where it goes to the rest of the body
Pubic symphysis and inter vertebral disc are the exmaple of
Cartilaginous joints
Cartilaginous joints, Synovial joints, Fibrous joints, Gliding joints
Cartilaginous joints: type of joint where bones are entirely joined by cartilage
- ex. Pubic symphysis, inter vertebral disc (between the vertebrates in spine)
Synovial joints: allow for movement
- ex. elbow joint, hip joint
Gliding joints: type of synovial joint where 2 bones meet on flat surface to allow for gliding
- ex. wrist bone
Fibrous joints: fixed or immovable joints as they do not allow any movement between the bones
- ex. skull bones, ankle bones, teeth roots
Cartilage is more difficult to heal than bone because cartilage:
Lacks vascular supply, meaning it has very limited blood flow
- a good vascular supply (blood flow) is important for the healing process
- bone has good vascular supply
Which feature is absent from cardiac muscles?
multinucleate cells
muscle fibers in cardiac muscle
- muscle fibers: cylindrical, branches, and uninucleate
- individual cardiac muscle cells are joined at their ends by intercalated discs to form long fibers
- organized into sarcomeres, the fundamental contractile units of muscle cells
contractile sarcomeres
tiny units within muscle fibers that are responsible for muscle contraction
- smallest functional unit of a muscle fiber
- present in skeletal and cardiac muscle, but not smooth muscle
skeletal muscle fibers
are multinucleate to accommodate for their large size, high metabolic needs, and efficient control
Sarcoplasmic reticulum of muscle fibers is mainly responsible for:
calcium storage
- plays crucial role in regulating calcium levels within muscle cells
- when muscle is stimulated, calcium ions are released from sarcoplasmic reticulum, allowing muscle to contract
The junction between two neurons is:
Synapse
chemically steroid hormones
3 major sex hormones: testosterone, estrogen, and progesterone
- cortisol
- 11-deoxycortisol
- aldosterone
corticosterone - 11-deoxycorticosteron
steroid hormones are fat-soluble and made from cholesterol
Under activity of parathyroid glands causes a drop in blood of:
Ca 2+
- parathyroid glands play a crucial role in regulating calcium levels in blood by producing parathyroid hormone
Which protein establishes the matrix of bone & cartilage?
Collagen
- collagen = fibrous protein that provides structural support and forms matrix of bone & cartilage
Non-competitive inhibitors react with enzymes at:
Allosteric site
- bind and change shape of enzyme reducing activity
Most enzymes work best at which temperature
37º C
(around 104º F)
formula to convert C to F
(°C × 9/5) + 32 = ºF
In term of enzyme actions, ‘maximum temperature’ refers to a temperature at which
Enzymes start to denature
When light falls on P-700, which event is likely to occur?
It’s oxidized as electrons are removed
Which 2 molecules are released after completion of light reaction and then utilized in the dark reaction of photosynthesis?
ATP and NADPH
end products of light reactions of photosynthesis?
ATP & NADPH
Synthesis of ATP during photosynthesis takes place in
thylakoid membranes
virion
The complete, mature, and infectious virus particle
All viruses are:
Parasites
The smallest known bacteria belong to the genus:
Mycoplasma
- These bacteria lack a cell wall and are among the tiniest free-living organisms.
Mesentric veins drain the blood from:
Large intestine
Secondary cell wall in plants is present between
the primary cell wall and plasma membrane
What distinguishes Prokaryotic cell walls from Fungal cell wall?
Prokaryotic cell walls contain peptidoglycan
Pollination is facillitated by:
Chromoplast
- attract insects and cause pollination
- are colored protoplasts
Tonoplast is the membrane separating:
vacuole and cytoplasm
tonoplast: membrane that surrounds vacuole of the plant
- function: keep vacuole acidic by bringing in protons so that it can keep breaking down food (pumps K+ into and out of cell)
Each centriole is composed of __________ microtubules
nine triplets (9 of 3 pairs)
centriole
cylindrical organelle composed mainly of protein tubulin
- organize microtubules that serve as cell’s skeletal system
The folds of the inner membrane of mitochondria are called
cristae
functions of the smooth endoplasmic reticulum (smooth ER)
- synthesis of essential lipids such as phospholipids and cholesterol (lipid metabolism)
- transmission of impulses (in muscle fibers)
- transport of materials
- also responsible for production and secretion of steroid hormones
charged pores
another name for ion channels
- play a crucial role in active and passive transport
lysosomes
involved in digestion and recycling of cellular waste materials and damaged organelles
Most abundant organic compound in mammalian cells are ___________
Proteins
Thermal stability of organisms in the environment is because of which characteristic of water?
specific heat capacity (water can absorb and retain heat)
what are C-H bonds in lipids important for?
they store a lot of energy and when they are broken, release a lot of energy for cells to use
lipids are energy-rich macromolecules
which carbohydrates are the sweetest among all carbohydrates?
monosaccharides
- they are single sugar units = simplest so bind to sugar receptors easiest
factors that affect vapor pressure
vapor pressure = how much molecules wanna escape from solid/liquid into gas phase
factors:
1.temperature: more temp = moving faster = easier to escape
2. IMF’s: stronger the IMF, the less likely it is to want to escape
3. adding more substances: molecules then interact with themselves and dont wanna let go
4. density: indirectly influences them because molecules with stronger IMF’s have greater densities
The boiling point of ether is less as compared to alcohols and phenols due to
weaker intermolecular forces
When 2 ice cubes are pressed over eaxh other they unite to form one cube due to
hydrogen bonding
structure of sodium chloride crystal
Each sodium ion is surrounded by six chloride ions and each chloride ions surrounded by six sodium ions
lattice energy & how to predict it
lattice energy: energy released when positive and negative ions come together to form a solid crystal from a gaseous state
higher the lattice energy, stronger the bonds between the ions in the crystal
factors that affect lattice energy:
1. charge of the ions: higher charges = higher lattice energy b/c attraction b/w ions is stronger
2. size of the ions: smaller ions can get closer together and have more attraction b/w them
- higher onto the periodic table
Thermal conductivity of metals is due to
freely moving electrons
thermal conductivity: measure of its potential to conduct heat.
- freely moving electrons are responsible for the conduction of heat and electricity in the metal
conduction: delocalized electrons in the transfer of the metal kinetic energy
what is thermal conduction
process by which heat energy is transmitted through collisions between neighboring atoms or molecules
delocalized electrons in the transfer of metals kinetic energy
kinetic energy & potential energy
kinetic energy: associated with motion of particles (related to heat bc more movement of particles is due to more heat)
higher the temp = more the kinetic energy
higher the position = more the potential energy
The high pressure of 200 atm in Haber’s process is used for
Better yield
habers process
method used to produce ammonia (NH₃) from nitrogen (N₂) and hydrogen (H₂) gases
- the reaction takes place at higher pressures (around 200 atm) and at high temperature (400-500°C)
- a catalyst, usually iron is used to speed up the reaction
N2+3H2 →2NH3
By which of the following factors eqilibrium state is attained earlier?
Catalyst
when temperature of reacting gases is raised by 10K, what will happen to the reaction rate?
it will double
- rule of thumb: increasing temperature by 10K roughly doubles the reaction
- other temperature increases will create different effects since molecules get faster and faster
The minimum amount of energy required by the colliding particles for effective collisions is called
activation energy
state vs pathway functions
state functions: depend only on the current state of a system, not on how the system got to that state
- ex. Temperature, pressure, volume, internal energy, enthalpy, and entropy.
pathway functions: depend on the specific path or process taken to reach a particular state
- work and heat
how to tell if an equation is lattice energy
- formation of ionic solid: lattice energy is defined as the energy released when one mole of ionic solid is formed from its constituent ions in the gas phase so 2 ions in the gas phase coming together to form one solid compound
- significant release of energy: this released energy is the lattice energy
When nitric oxide reacts with ozone, the order of reaction will be
2nd order
nitric oxide - NO
ozone - O3
yields nitrogen dioxide (NO2) and O2
During electrolysis, reduction occurs at the
cathode
AN OX, RED CAT (if u put a cat in a blender it will turn red)
The reason of highest electronegativity value of fluorine is
smaller size and higher nuclear charge in the respective period
- small size: smaller means electrons are very close to the nucleus = pull of them is stronger
- more nuclear charge = more protons in its nucleus
Valence shell electron pair repulsion theory explains
ITS LONG FOR VSEPR
explains shapes
coordination number
simply the count of how many atoms or ions are directly attached to a central atom or ion
coordination number of Na
6
each sodium ion is surrounded by 6 Cl- ions
cracking & catalytic cracking
cracking: process where large, heavy hydrocarbon molecules found in crude oil are broken down into smaller, lighter molecules
catalytic: a catalyst is used that speeds up the chemical reaction without being consumed in the process
used to obtain better quality gasoline
Homocyclic organic compounds are sub divided into two types
Alicyclic and Aromatic
homocyclic organic compounds: type of chemical compound where the ring is made up of only carbon atoms
alicyclic compounds (non-aromatic): single carbon rings without special stability
aromatic compounds: have special stability due to unique arrangement of alternating double and single bonds
alkylation & acylation + usefulness
alkylation: adding an alkyl (group of carbon-hydrogens, whatever count) group to a molecule
- useful: make molecules larger and often more useful for different purposes, like creating higher-octane gasoline
acylation: adding an acyl group (group containing a carbonyl group, C=O, and a carbon chain) to a molecule
- useful: acylation is important in making pharmaceuticals, perfumes, and other chemicals
benzene
ring of 6 carbon atoms
Acetophenone can be formed by which of the following reaction of benzene?
Friedal craft acylation
- acetophenone is a ketone because it ends in one and benzene is an aromatic ring
Friedal Crafts Acylation
involves the addition of an acyl group (removal of one or more hydroxyl groups from an oxyacid (C=O-R) to an aromatic ring (ring of atoms joined by covalent bonds)
- in a Friedel-Crafts acylation reaction, the aromatic ring is transformed into a ketone
cycloalkanes + generic formula
cycloalkanes: type of hydrocarbon where the carbon atoms are arranged in a ring or loop structure. unlike alkanes, which have a straight or branched chain of carbon atoms, cyclohexanes form a closed ring
generic formula: Cn H2n
what do these generic formulas represent + short description of what they are:
- Cn H2n+2
- Cn H2n
- Cn H2n-2
- alkanes (saturated hydrocarbons, have all carbon-carbon single bonds)
- alkenes (have at least 1 carbon-carbon double bond) or cycloalkanes (have a ring structure)
- alkynes (have at least 1 carbon-carbon triple bond) or dienes (compounds with 2 double bonds)
phenols vs alcohols
alcohols: -OH group attached to a simple carbon chain
phenols: like alcohol but instead of being attached to simple carbon chain, -OH group is attached to a benzene (ring-shaped molecule made of 6 carbons)
what reaction differentiates alcohol from phenol?
halogenation reaction
because phenols react with halogens due to increased reactivity of aromatic ring whereas alcohols do not react the same way
Lucas test
used to differentiate between primary, secondary, and tertiary alcohols
using a solution of anhydrous zinc chloride in concentrated HCl
how it works:
- tertiary alcohols react immediately
- secondary react more slowly
- primary alcohols do not react at room temperature
difference between primary, secondary, and tertiary alcohols
based on number of carbon atoms attached to the carbon that holds the -OH group
primary: carbon with the -OH group is attached to only 1 other carbon atom (everything else is either H or something else)
- ex. ethanol
secondary: carbon with the -OH group is attached to 2 other carbon atoms
- ex. isopropanol
tertiary: carbon with the -OH group is attached to 3 other carbon atoms
- ex. tert-butanol
halogenation (how it works + uses)
used to add halogen atoms (like chlorine or bromine) to organic compounds, typically alkanes or alkenes
how it works: halogen atoms replace hydrogen atoms in the organic molecule, often requiring heat or light to initiate the reaction
useful: halogenated compounds are important in making many chemicals, including solvents and refrigerants
nitration (how it works + uses)
adding a nitro group (NO2) to an organic compounds, such as benzene
how it works: mixture of nitric acid and sulfuric acid is used to add the nitro group to the aromatic ring
useful: nitrated compounds are used in making explosives and dyes
iodoform test + how it works
used to identify methyl ketones or compounds that can be oxidized to methyl ketones
how it works: when treated with iodine and a base, methyl ketones produce a yellow precipitate of iodoform (CHI3), indicating their presence
methyl ketones: molecules where a CH3 group is directly attached to a carbon thats double bonded to oxygen (C=O)
- ex. acetone
The order of reactivity of alcohols when C-O bonds break is:
tertiary → secondary → primary
(most easily broken first)
generic formulas of the following:
- ether
- carboxylic acid
- ketones
-
Ether: Cn H2n+2 O
R - O - R’ -
Carboxylic Acid: Cn H2n O2
R - COOH -
Ketones: Cn H2n O
R - CO - R’
The amount of energy associated with quantum of radiation is directly proportional to:
frequency
uses E=hf
E - energy of quantum (energy associated with quantum of radiation, but really just energy)
h - planck’s constant (6.626 x 10 ^-34)
f - frequency
azimuthal quantum number and magnetic quantum number
azimuthal quantum number (l): determines shape of an electron’s orbital
- takes on values from 0 up to n-1 where n is principal quantum number (main energy level)
magnetic quantum number (ml): determines orientation (direction) of orbital in space. for any l, ml can take on integer values from -l to +l
If value of azimuthal quantum number is 2 then what will the total values of magnetic quantum number be?
5
because l is 2 so ml is anywhere from -2 to 2 which is 5 values in the middle
Total number of directions of f-orbitals in space are
7
- f orbitals have an l number of 3
- since ml gives orientation (direction) of orbital in space, value can take on any number from -3 to 3 so:
-3, -2, -1, 0, 1, 2, 3 so 7 number of directions
schrodinger’s wave equation
- predicts behavior and properties of particles, such as electrons, at the atomic and subatomic levels
- shows that particles have wave like properties
Which quantum number is not obtained from Schrodinger Wave equation?
spin quantum number (ms)
Aufbau principle
states that electrons fill atomic orbitals of the lowest available energy levels before occupying higher levels
- aufbau means “building up” in German
Hund’s Rule
states that degenerate orbitals (orbitals having the same energy level) will occupy empty orbitals singly as far as possible before pairing up
- ex. for all of the p’s, place one electron in every box and then double at the end
n + l rule (madelung rule)
helps predict order in which orbitals are filled based on their energy levels
n = principal energy level
l = azimuthal quantum number
orbitals are filled in order of increasing n + l value. if 2 orbitals have the same n + l value, the orbital with the lower n value is filled first
ex:
- 3s orbital (n=3, l=0) has a n + l value of 3
- 2p orbital (n=2, l=1) has a n + l value of 3
- since both have the same n + l value, the 2p orbital is filled before the 3s orbital because it has a lower n value
pauli exclusion principle
states that an orbital can hold a maximum of 2 electrons, and these electrons must have opposite spins
- explains why electrons fill orbitals in pairs with opposite spins
kinetic theory of gases (KMT)
explains behavior of gases as particles in constant random motion
key concepts:
- gas particles are always in motion, moving in random directions at various speeds
- elastic collisions: these particles collide with each other and walls of container. elastic meaning no energy is lost in the collision
-
pressure: pressure of gas is due to collisions of particles with walls of container
-> more collisions = higher pressure
temperature: more average kinetic energy (particles move faster) means higher temp
crystal field theory
explains electronic structure and properties of transition metal complexes (compounds formed by transition metals with ligands)
key points:
- transition metal ions can form complexes by binding to ligands (molecules or ions that donate electron pairs)
- d orbital splitting: when ligands approach a transition metal ion, they interact with the metal’s d-orbitals, causing orbitals to split into different energy levels
color and magnetism: splitting of d-orbital affects color and magnetic properties of complex
- Different arrangements of ligands lead to different splittings and, hence, different properties.
The SI unit for pressure is
pascal
1st law of thermodynamics
states that energy is conserved - energy cannot be created or destroyed in a closed system, only converted between different forms like heat and work
∆U = Q - W
∆U = change in internal energy
Q = heat added to system
W = work done by system
The S.I unit capacitance of a capacitors is:
Farad (F)
1 kWh (kilowatt-hour) is equal to how many Joules
3.6 x 10^6 J or 3.6 million joules
- unit of energy often used for electricity consumption
The weber is unit of measure of:
magnetic flux
A current generator is a device that converts:
mechanical energy into electrical energy
isochoric (also called isovolumetric) process
thermodynamic process in which volume of the system remains constant
- no work is done by the system because no change in volume because in confined/closed container
- any change in the system’s internal energy is due to heat transfer
how to solve this problem: If 42 J of heat is transferred to the system during expansion, what is the change in internal energy when work done is 32 J?
calculating internal energy using work and heat added: ∆U = Q - W
∆U = change in internal energy
Q = heat added to the system
W = work done by the system
∆U = 42 J - 32 J = 10 J
While studying charging and discharging of a capacitor, Rc = Resistance x Capacitance is known as?
Time constant (τ)
capacitor + charging & discharging
device that stores electrical energy that typically consists of 2 metal plates separated by an insulating material called a dielectric
(think small bucket that can quickly fill up with electrical charge and then pour it out when needed)
charging: charging is when it is connected to an power source and starts storing electrical energy
discharging: when you disconnect the power source and it releases the stored electrical energy
Resistance (R), Capacitance (C), and Time Constant (τ) in capacitor
Resistance (R): Measure of how much a component resists flow of electric current
Capacitance (C): measure of capacitor’s ability to store an electric charge (capacity)
Time Constant (τ): measure of how quickly the capacitor charges or discharges
- time it takes for the voltage across capacitor to either charge up to about 63% of its maximum value or discharge down to about 37% of its initial value
dielectric constant (relative permittivity)
measure of how well a material can store electrical energy in an electric field compared to a vacuum
how good a material is at storing electric charge
- higher the dielectric constant, more electrical energy the material can store
proportionality constant
constant value that relates 2 variables that are directly proportional to each other
basically the variable in any equation really like A = kB where k is constant
parallel combination of 2 capacitors, their equivalent capacitance is equal to
C1 + C2
parallel combination: both capacitors are connected directly across the same 2 points, so they both experience the same voltage
- total charge stored is the sum of the charges stored by each capacitor
resistance of a wire formula
R = ρ L/A
R = resistance
ρ (rho) = resistivity of the material (a constant for a given material)
L = length of the wire
A = cross sectional area of the wire
change in wire lengths can be calculated using this formula
- resistance directly proportional to cross-sectional area and inversely proportional to length
direction of charged particle when it enters a magnetic field based on whether it enters parallel or perpendicular
- when a charged particle enters a magnetic field, it experiences a force but the direction of force depends on the
magnetic field strength (H) & magnetic induction (B)
magnetic field strength: effort or force you use to create a magnetic field
- push you apply to a swing to make it move
magnetic induction: result of that efforts - how strong the magnetic field actually becomes
- like how high the swing goes after you push it
magnetic flux
total amount of magnetic field passing through a certain area
- think of it like water flowing through a net, the more water (magnetic field lines) that pass through, the greater the flux
- measured in webers (Wb)
magnetic force
force exerted by a magnetic field on a moving charged particle or another magnetic object
- the push and pull that magnets exert on each other or on other magnetic materials
- measured in newtons (N)
the dimension of magnetic field strength is the same as that of
magnetic induction
both have newtons per ampere-meter (N/A*m)
Lenz’s law
basically says that if something causes a magnetic field to change, the induced current will try to resist or counteract that change
- ex. if you push a swing in one direction, the swing will naturally move in the opposite direction to resist that push
is also a statement of the law of conservation of energy because energy cannot be created or destroyed so this is trying to prevent that from happening so energy input equals energy output
Fleming’s right hand rule
simple way to remember the direction of induced current when a conductor (like a wire) move through a magnetic field
thumb: points in the direction of motion of the conductor (the way its moving)
first (index) finger: points in the direction of the magnetic field (from north to south)
second (middle) finger: points in the direction of the induced current (flow of electrons )
If the car is slowing down along the negative x axis then acceleration will be along
positive x axis
- car is slowing down so acceleration is acting in the opposite direction to motion so it has to be in the opposite direction to motion
how to make this more grammatically correct: Him and I went to the concert last night
He and I went to the concert last night
the instantaneous velocity along the curved path is
along the tangent
because thats the derivative and the derivative is the instantaneous velocity
- object along curved path keeps changing direction but at any specific point, its instantaneous velocity (speed and direction at that exact moment) points in the direction tangent to the curve
relationship between pressure and speed of sound
increase or decrease in pressure has no effect on the speed of sound
2 things that change the speed of sound moving through a medium
medium’s temperature: higher temps make molecules move faster, which allows sound waves to propagate more quickly
medium’s density & elasticity: this relates to how easily molecules can be compressed and how quickly they return to their original state
crest & trough of a transverse wave + compressions & rarefactions of a longitudinal wave
transverse:
crest: highest point of the wave (the peak)
- above the mean level
trough: lowest point of the wave (the dip)
longitudinal:
compressions: regions where particles are closest together, where wave reaches maximum in terms of density or pressure
rarefactions: regions where particles are spread out, where wave reaches a minimum in terms of density or pressure
longitudinal vs transverse waves
transverse waves: move up and down or side to side perpendicular to the direction wave is traveling
- ex. light waves, water waves
longitudinal waves: move back and forth parallel to direction wave is traveling
- ex. sound waves
how to solve this question:
A 32 g radioactive element decays and remains 2g after 60 days. What is half-life of this radioactive element?
15 days
to find half-life, calculate how many times the initial quantity must halve to reach 2g
32g → 16g (halved once) → 8g (halved twice) → 4g (halved thrice) → 2g (halved 4 times)
so element halved 4 times to reach 2g. Since this took 60 days, half-life is 60 days/4 = 15 days
what is a perfectly elastic collision and what is conserved during it
when 2 objects collide and bounce off each other without any loss of energy and with the same speed they had before the collision
momentum, kinetic energy, and total energy are all conserved
slope of displacement-time graph is equal to
velocity
at what point during the motion of projectile is its vertical component of velocity zero?
highest point
change in momentum is equal to
product of force and time
product of force and time is known as impulse. impulse changes the momentum of an object
impulse-momentum theorem
states that the impulse applied to an object is equal to the change in its momentum
J = ∆p = p final - p initial
J = impulse
p = momentum which is p = m x v
( mass x velocity )
- means that when a force is applied to an object for a certain amount of time, it changes the object’s velocity, and therefore, its momentum
force
what causes an object to accelerate (change its velocity)
- the “push” or “pull” acting on an object
F = m · a
angular momentum
related to objects that are rotating or spinning
- depends on object’s rotational velocity, mass, and the distance from the center of rotation (radius)
angular momentum = moment of inertia x angular velocity
- different from linear momentum, which deals with objects moving in a straight line
range of a projectile on a horizontal plane is the same for which pair of angles
for angles that are complimentary (meaning they add to 90º)
Work done (W) to lift an object to a certain height is equal to _______________________________________________________.
the potential energy gained by the object at that height
- this is because work done against gravity to raise the object is stored as potential energy
how to answer this question:
the object has 1 J of P.E. What is the work done in terms of height?
answer: 1 J
W = P.E.
- work done to lift that object to that height is equal to the potential energy that that object gains
