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

Radiation occurs when energy is transferred by waves from a source to the food. The waves themselves are not actually heat energy but are changed into heat energy when they strike the food being cooked. (Light waves, radio waves, and X-rays are examples of radiation not used for cooking.)

Two kinds of radiation:

Infrared: In a broiler, an electric element or a ceramic element heated by a gas flame becomes so hot it gives off infrared radiation, which cooks the food. High-intensity infrared ovens are designed to heat food rapidly.

Microwave: radiation generated by the oven penetrates partway into the food, where it agitates the molecules of water. The friction this agitation causes creates heat, which cooks the food. Because microwave radiation

JANUARY

Adrian is 13 years old. I prepare his resolutions for the new year. He has a point on his chin. He feels bad because his parents separated. His dog is sick because he ate a model of a boat from Adrian's father. Lucas, the neighbor, visits Adrian's mother every day. Adrian meets Pandora and falls in love, but she ends up with Adrian's best friend, Nigel. At school, Adrian has a support group for the elderly where he helps Bert Baxter. Lucas and his wife divorce, and Adrian's father is jealous of him.

FEBRUARY

Adrian's parents no longer have housework. She just spends the day with Lucas looking at porn magazines. Adrian has his first porn dream. Lucas stays with Adrian's family because his wife took all the furniture. He only has a Valentine'... Continue reading "Adrian's Coming of Age Story: A Year of Challenges and Love" »

Adjectives

The simplest definition of an adjective is that it is a word that describes or clarifies a noun. Adjectives describe nouns by giving some information about an object’s size, shape, age, color, origin, or material.

It’s a big table. (size)

It’s a round table. (shape)

It’s an old table. (age)

Possessive adjectives - my, your, his, her, its, our, your, their -

Modify the noun following it to show possession.

Examples:

I'll get my bag.

Is this your luggage?

Comparative adjectives

Used to compare differences between two objects they modify (larger, smaller, faster, higher).

My house is larger than hers.

This box is smaller than the one I lost.

Your dog runs faster than Jim's dog.

Superlative adjectives

Used to describe an object at the upper... Continue reading "Understanding Adjectives and Adverbs: Definitions and Examples" »

What are New Year's resolutions?

New Year's resolutions are a person's (good) intentions for the coming year.

Why does Adrian think that his spot is growing?

Adrian thinks that his spot is growing because his mother doesn't know about vitamins.

When the dog has the operation, what does the vet find? Why?

The vet finds many things in the dog's stomach. There were even plastic pirates from Adrian's father's model ship. The dog had eaten these things.

Exactly how old is Adrian at the beginning of his diary?

Adrian is 133/4 years old at the beginning of his diary.

Why did Adrian think Nigel was being polite when he told him that he was going to the doctor?

Adrian thought that Nigel was being polite because Nigel said he couldn't see Adrian's spot.

Why did

Evolution of Animals

Past Forms and Modern Counterparts

1. Changes in Animal Views

Our view of modern animals has changed due to the evolutionary adaptations within their species, as revealed by scientific studies.

2. T-Rex of the Ocean

Ancestors of the blue whale were nicknamed the "T-Rex of the ocean" because they possessed razor-sharp teeth.

True or False Statements

Justify your answers with evidence from the provided text.

3. Existence of Animals 50 Million Years Ago

True. Fifty million years ago, familiar animals existed, but in almost unrecognizable forms.

4. Resemblance of Large Dogs to Modern Whales

True. Whales, which now live in the water, once had legs and lived on land, possibly resembling large dogs.

5. Immediate Loss of Whale Hind Legs

False.

1) A wave has the form

When x = 0, the wavelength is

By applying continuity conditions at x = 0, find the amplitude A_x>0 (in terms of A) and phase Φ of the wave in the region x > 0. Use any variable or symbol stated above as necessary.

2) An electron is trapped in an infinite well of width L = 1.87nm. What are the three longest wavelengths permitted for the electron's de Broglie waves?

The wave function must be zero everywhere the potential is infinite. So the wave function is zero outside the well. Since the wave function must be continuous, the wave function inside the well must go to zero at the edges of the well. Thus, only certain discrete wavelengths are allowed.

3) A particle is described by the wave function ψ(x) = b(a² - x²) for

Matthew Arnold's Touchstone Method of Criticism was really a comparative system of criticism.  Arnold was mostly a classicist.  He admired the ancient Greek, Roman and French authors as the models to be followed by the modern English authors.  The old English like Shakespeare, Spenser or Milton were also to be taken as models.  Arnold took selected passages from the modern authors and compared them with selected passages from the ancient authors and thus decided their merits.  This method was called Arnold's Touchstone Method.             However, this system of judgement has its own limitations.  The method of comparing passage with a passage is not a sufficient test for determining the value of a work as a whole.  Arnold... Continue reading "dsf" »

Vocabulary

• Motion: An object’s 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.
• Speed: The distance traveled divided by the time interval during which the motion occurred.
• Velocity: The speed of an object in a particular direction.
• Acceleration: The rate at which velocity changes over time; an object accelerates if its speed, direction, or both change.
• Force: An action exerted on a body in order to change the body’s state of rest or motion; force has magnitude and direction.
• Friction: A force that opposes motion between two surfaces that are in contact.
• Net Force: The combination of all forces acting

LASER = Light Amplification by Stimulated Emission of Radiation

A laser is actually an oscillator rather than a simple amplifier. The difference is that an oscillator has positive feedback in addition to the amplifier.

Light is understood in a general sense: electromagnetic radiation with a wavelength around 1 μm. Thus, one can have infrared, visible, or ultraviolet lasers.

The atomic medium with population inversion used in the laser is called the active medium. The positive optical feedback is obtained by placing the active medium between two mirrors. One of them (M1) totally reflects back the light (R1 = 1) to the active medium, while the other one (M2, called the output coupler) has a reflectivity less than unity (R2 < 1) and allows some... Continue reading "Introduction to LASER Technology: Types, Operation, and Applications" »

DEFINITIONS

DISTANCE

How much ground an object has covered/traveled.

DISPLACEMENT

The change in position of an object.

SCALAR QUANTITY

Quantity that only has magnitude and no direction.

VECTOR

Physical quantity that has both magnitude and direction.

CONSTANT SPEED

Speed that does not change.

VELOCITY

Speed in a given direction.

FRAME OF REFERENCE

A background used to judge motion/speed (precise location of an object).

INSTANTANEOUS SPEED

Speed at a given moment.

ENERGY

The capacity/power to do work/move an object by applying force.

MATTER

Anything that has mass and takes up space (how much matter).

WEIGHT

Measure of how gravity pulls matter.

SPEED

Amount of distance traveled in a certain amount of time.

AVERAGE SPEED

Total distance divided by total time.

TIME DISTANCE