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

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" »

Henry Cavendish

conducted an experiment that determined the value of the constant...

Rev of Heavenly Spheres

Axis of Rotation

Tycho Brahe

Gravitational Force

Centripetal Force

Uniform Circular Motion

Inertial Mass

Centrifugal Force

Apparent Weightlessness

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

Human Evolution: From *Orrorin* to *Homo Sapiens*

The Earth was formed 4,500 million years ago. There is evidence that the hominid family emerged 6 million years ago, with our species, Homo sapiens sapiens, appearing only 150,000 years ago. Our species is characterized by the development of the brain, which allows for complex social behavior, consciousness of our own existence, and a great capacity for communication. The evolution of our species includes the following:

Key Hominid Species

1. Orrorin tugenensis: Lived more than 6 million years ago (MA). They were omnivorous, lived in jungles, measured 1.4 meters, were bipedal, and were descendants of the current chimpanzees, but with differences in the pelvis, humerus, and femur.
2. Ardipithecus ramidus: