Physics final

If an ice skater brings her arms in while she spins why does her angular speed increase?

When she brings her arms in she greatly reduces her moment of inertia (aka her resistance to spin), which results in her speed dramatically increasing

What do waves transfer?

Energy

Explain the difference between a transverse and a longitudinal wave

A transverse wave is one in which the particles of the medium move in a PERPENDICULAR direction to the wave motion. a longitudinal wave is one in which the particles of the medium move back and forth PARALLEL to the wave motion.

Define a medium. Give two examples of waves that require a medium. Give one example of a wave that does no require a medium.

A medium is a physical environment in which stuff happens. mechanical waves require mediums, electromagnetic waves don’t. mechanical waves are things like sound waves or water waves. Electromagnetic waves are things like light waves.

What features do transverse and longitudinal waves share and which features correspond.

They both have wavelengths and amplitutes. Crests are like compressions and troughs are like rarefactions.

Define constructive interference. define destructive interference. How does interference occur? Why does interference occur? What happens to teh individual waves after interference?

Constructive interference: occurs when waves combine to make a wave with a larger amplitude. The waves have to be “in phase: meaning their peaks (crests/compressions) or valleys (troughs/rerefractions) have to line up. Destructive interference is the opposite

Define resonance

resonance can be defined in at least two different ways. The first is the phenomenon that occurs when the frequency of a force applies to an object matches the natural frequency of the object. The second os on terms of standing waves. When waves reflect, if they have proper wavelengths, they can constructively interfere with themselves.

On a string at what wavelength will resonance occur?

Resonance will occur if the wavelength divides into the length of the string evenly or with a .5 at the end.

Explain why sound travels more quickly in solids than they do in liquids or gases

Sound is mechanical so it travels by disturbing the particles of the medium through which it travels. When particles are tightly packed together, they easily and quickly transfer energy.

Explain the doppler effect. Describe a moving sound source relative to a stationary observer in terms of observes frequency of sound.

The doppler effects is the apparent change in the frequency of a wave dies to relative motion between the source and the observer. If the source of a sound wave is moving toward you, you’d hear a higher pitch. If it were moving away from you, youd hear a lower pitch.

Describe is ascending wavelength order, the different parts if the electromagnetic spectrum. What do all the different parts have in common

Gamma (shortest wavelength, highest energy)

x-rays

ultraviolet

visible light

infrared

microwave

radio

Speed'- all electromagnetic radiation travels at the speed of light

How does distance affect the force between particles? How does the magnitude of charges affect the force between particles? How does the polarity of the charges affect the motion of the particles?

-Inverse square law! The force is inversely proportional to the square of the distance

-The force is directly proportional to the magnitude of either charge

-Like charges repel

When charging masses (or objects) what type of charges can actually be moved? Why?

Electrons are moves, protons are kind of anchored down in typical circumstances and interactions. This is because a proton has as much mass as over 1,800 electrons.

Two point charges of equal magnitude are separated by distance r. By what factor will the force increase of the magnitude of the charges is tripled.

Since the force is directly related to the charge, of one charge is tripled, the force will triple. If they’re both tripled the force will multiply by 9.

The same two particles of equal magnitude are separated by 3 cm. if they are moved so that they are now 15 cm apart, by what magnitude has the electrical force between them changed?

Force is inversely related to distance squared, so if distance is quintuples, the force is divided by 25.

What factors effect electric field strength> How do you determine the relative ratio of electrical field strength occurring between two particles?

distance from a charge and magnitude of source charge

What is the function of a capacitor in a circuit? When does the charge build-up stop between the plates of a capacitor? What happens to current flow when the capacitor is fully charged?

They store up electrons for rapid discharge later on. Capacitors are used in camera flashed and many other things. Each capacitor has an inherent capacitance. Positive charge builds up one plate and negative charge build on the other. They build at equal rates until the potential across the plates in the same as the potential across the battery. because one side of the capacitor is positive and the other is negative, there is no net current flow.

Where is the highest electric potential?

Highest close to the point charge

When moving a test charge, when is the change electric potential minimal?

When the test charge moves along an equipotential line.

Describe work in terms of electrical potential and equipotential lines.

When point charges move across equipotential lines, their electric potentials change. When electric potential changes, work is done; When electric potential doesn’t change, no work is done

the direction of an electric field at any one spot is determined to be the direction of a tiny ______ test charge would go if places at that spot

positive

There are mainly two types of electric fields we are going to be concerned with. They are

a) electric fields caused by ____ charges whose field strength decays as a function of _____ called the inverse squared event

b) electric fields that exists between two oppositely charged conducting sheets called _____, between which, the electric field has a _____ value

point, distance squared. capacitors, constant

_____ is a property of a material, regardless of its length or area

_____ is a property of an object that depends on its length and area

resistivity, resistance

capacitance and plate area are ____ proportional. This means that ____ the surface area will ______ the capacitors ability to hold charge

Directly, increasing, increase

Capacitance and plate spacing are ______ proportional. This means that ______ the space between the plates will ______ the capacitors ability to hold charge

inversely, increasing, decrease