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# P.S. Final

The length of a straight line from the starting point to the ending point is: displacement
The length of the path between two points is: distance
The ratio of the distance an object moves to the amount of time an object moves is the object’s: speed
If a graph has time on the ‘x’ axis and distance on the ‘y’ axis, the slope is: slope = (change in y)/(change in x) slope = (change in d)/(change in t) d/t is speed
The ratio of the change in velocity per unit time is: acceleration
velocity and acceleration are both vectors. That means that they have both _____ and _____ magnitude and direction
Acceleration is the rate at which velocity changes. That means, and object can be changing ______, ______, or _____. speed, direction, or both
If an object is traveling at a constant speed in a circular path, is it accelerating? Why or why not? yes, it is changing direction
A biker travels 20 km in 35 min, then rests for 5 min, then travels 15 km in 20 min. What is their average velocity for the trip? average velocity = (total distance)/(total time) average velocity = 35 km/hr
A car accelerates from 0 km/hr to 100 km/hr in 10 seconds. What is their average velocity for this time period? And what is their acceleration? average velocity = [beginning velocity + ending velocity]/2 average velocity = [0 km/hr + 100 km/hr]/2 average velocity = 50 km/hr acceleration=change in velocity/change in time acceleration = [100 m/s]/10s acceleration = 10 m/s/s or 10 m/s²
When an unbalanced force acts on an object, the object will: accelerate
The force that opposes the motion of objects that touch as they move past each other is: friction
An object in motion tends to stay in motion and an object at rest tends to stay at rest unless: acted upon by an outside force
The measure of the inertia of an object, which depends on the amount of matter that an object contains, is: mass
An object’s mass times the acceleration due to gravity is the object’s: weight
The net force acting on an object divided by the object’s mass is: acceleration
When the force of air resistance equals the force of gravity for a falling object, what happens? The object has reached terminal velocity; it no longer accelerates
If a ball is thrown, it will follow a curved path. This type of motion is called ____. The two things that cause it to follow a curved path are _____ and _____ Projectile Motion, An initial forward velocity, and the downward vertical force of gravity
What is always conserved in collisions? What is not always conserved in collisions, and in what type of collision is it not conserved? momentum is always conserved in collisions Velocity is only conserved in elastic collisions, velocity is not conserved in inelastic collisions
A ball collides with another ball at rest. The second ball starts moving, and the first ball bounces back. What sort of collision is this, and why does the first ball bounce back? This is an elastic collision. It is an example of an action-reaction pair of forces. The first ball exerts a force on the second one. The second one also exerts a reaction force on the first one, which makes it bounce back.
The unit of pressure is the _____. The units that make this up are _____. a Pascal is also N/m²
A force of 100 N acts over an area of 2m². What is the pressure? Pressure = Force/Area Pressure = 100N/2m² Pressure = 50 N/m² = 50 Pa
Fluid pressure only depends on these two things: depth of fluid, and type (density) of fluid
Since liquid cannot be compressed, any change in pressure at any point is transmitted equally and unchanged in all directions throughout the fluid. Name this principle, and the science that uses this principle Pascal’s principle Hydraulics
If a liquid is moving, the pressure in the fluid _____. This is what causes ‘lift’ for an airplane. What is the name of this principle? decreases, Bernoulli’s principle
Imagine two small foam balls hanging from strings at the same height with about 3 cm of space between them. What will happen if you blow air through the space between them, and why? The balls will move towards each other the fluid (air) between the styrofoam balls is moving, so the pressure drops. Air pressure is still normal on the outsides of them, so air pressure pushes them towards each other
Why is it easier to float in salt water than in fresh water? Saltwater has greater density, so it creates a greater buoyant force when displaced
What two forces determine whether an object floats or sinks? Weight and buoyant force
When an object is submerged, how does its mass change? How does its apparent weight change? Mass doesn’t change. The apparent weight decreases.
If two cubes of the same volume are placed in a liquid, one sinks and one floats. Which one has the greater buoyant force acting on it? The one that sank; it displaced a greater volume of fluid
Work is calculated by multiplying _____ times _____. What are work’s units? Work = force * distance Work is measured in Joules
Work requires _____ and depends on _____ work requires motion work depends on direction
The rate of doing work is called _____ and is measured in _____ Power = work/time Power is measured in Watts
James Watt defined a horsepower based on the power output of a very strong horse. How many watts are in a horsepower? 1 watt = 746 hp
Machines make work easier to do. They can do these three things: 1. Increasing Force: A small force exerted over a large distance becomes a large force exerted over a small distance 2. Increasing Distance 3. Changing Direction
the work done by a machine is always less than the work done on the machine because of _____ Friction
3000 J of work is put into a machine, and 1500 J of work is done by a machine. How efficient is it? Efficiency=(work out)/(work in) * 100% 50 %
How much work is being done if you are holding a 10 kg box above your head? none, it isn’t moving
Give an example of each of the 3 different types of levers First Class Lever: teeter-totter Second Class Lever: wheel barrow Third Class Lever: broom
What can you multiply with a wheel and axle? How? Multiply speed by turning the axle, or multiply force by turning the wheel
The unit of energy is the _____. What else is measured with these units? Joule. Work, Heat and Energy
In terms of work, energy is: Energy is the ability to do work
Another unit of energy is equal to 4.184J. What is it? a calorie
A calorie is defined as: A calorie is the amount of energy required to raise the temperature of 1 g of water by 1° C (A food calorie, also called a ‘kilocalorie,’ is 1000 calories)
What is potential energy? Give two examples Potential energy is energy that is stored as a result of position or shape Gravitational Potential Energy, Elastic Potential Energy
Using 10 m/s² for gravity, if a 15 kg rock is on a cliff 10m high, what is its PEgrav? PEgrav = mgh =(15kg)(10m/s²)(10m) = 1500J
Kinetic Energy is determined by two things. What are they? mass and velocity
If you triple the speed of an object, what happens to its KE? If you triple the speed of an object, the KE will be 9x as much.
What is Mechanical Energy? When is it conserved? Mechanical Energy is the energy associated with position and motion of everyday objects. (ME = KE + PE) It is conserved in the absence of friction
How is a rock’s KE at the top of the cliff related to the same rock’s PE at the bottom of the cliff if it falls? KE at the top and PE at the bottom are both equal to zero
The thermal energy of an object depends on these three things: Mass, temperature, and phase
Why must railroad tracks be inspected when it is either very hot or very cold? The rails will either expand or contract because of the temperature
What is temperature related to? (Explain about the particles that make up the material) Temperature is related to the average kinetic energy of the particles in an object due to their random motions through space
Two things have different temperatures. Will the object with a higher temperature always have more thermal energy? Why or why not? No. Something with a greater volume may have a lower temperature, but greater thermal energy. For example, think of a cup of hot tea and a bathtub of warm water
What is Specific Heat? Specific Heat is the amount of heat needed to raise the temperature of 1 gram of a material by 1°C
If specific heat is lower, does it take more or less energy to make the temperature rise? less
What is required for heat to move from one thing to another? And, heat naturally flows from _____ to _____ a difference in Temperature Hotter objects to cooler objects
Give three ways of making popcorn, that show the three ways to transfer heat microwave (radiation) kettle on the stove (conduction) hot air popper (convection)
If energy is added to a system, it can do one of these two things: It can either do work on the system, or increase the thermal energy of the system.
What are the three laws of Thermodynamics? Energy is conserved Thermal energy can flow from colder objects to hotter objects only if work is done on the system Absolute zero cannot be reached
Mechanical waves travel through a: Medium (They cannot travel through a vacuum!)
A wave carries _____ from one place to another, but not _____ Energy, not Matter
Waves either travel like a snake, or like an earthworm. What are these two kinds of waves? snake: transverse waves earthworm: longitudinal waves
The areas of greatest displacement from equilibrium for a longitudinal wave are called _____ or _____ The areas of greatest displacement from equilibrium for a transverse wave are called _____ or _____ longitudinal: compressions & rarefactions transverse: crests & troughs
The time required for one cycle of a wave is its _____ which is measured in _____ Period, measured in seconds
The number of cycles per unit time is called _____, which is measured in _____ frequency, measured in Hertz (Hz), which is 1/s
The maximum displacement from rest is a wave’s _____. The distance between a point on one wave and the same point on the next wave is the wave’s _____ amplitude wavelength
If a wave stays in the same medium, its _____ stays constant In this case, if frequency goes up, what happens to wavelength? speed If frequency increases, wavelength decreases
What happens when a wave bounces off something that it can’t pass through? What may change? What doesn’t change? The wave is reflected. The wave can be flipped upside-down if there is a fixed boundary. The frequency and speed will not change. (A reflected sound wave is an echo)
When a wave is reflected exactly back on itself, what is formed? This sort of wave will form if the length of the vibrating medium is exact multiples of what? A standing wave forms if a wave is exactly reflected back on itself, and if the length of the vibrating medium is exact multiples of 1/2 the wave’s wavelength
Like mechanical waves (like sound waves), electromagnetic waves don’t carry material, they just transfer _____. But unlike mechanical waves, electromagnetic waves can travel through a _____. Waves transfer energy Electromagnetic waves can travel through a vacuum (or empty space; they don’t require a medium)
Electromagnetic waves consist of changing _____ fields and _____ fields, which are at right angles to each other, and to the direction of the wave Electric fields and magnetic fields
The main evidence for the wave model of light, Shown by Thomas Young’s experiment of 1801, is _____ The main evidence for the particle model of light (that light travels as packets of energy, called photons) is the _____. wave: interference particle: the photoelectric effect
What are two ways to increase the energy of a wave? greater amplitude greater frequency
The three types of electromagnetic radiation that have shorter wavelengths than visible light, listed from longest to shortest, are _____. Give an example of a use for each type. Ultraviolet Rays are used in health, medicine, and agriculture,X-Rays areused in medicine, industry, and transportation tomake pictures of the inside of solid objects,Gamma Rays are used in the medical field to kill cancer cells and make pictures of the b
The two types of electromagnetic radiation that have longer wavelengths than visible light, listed from longest to shortest, are _____. Give an example of a use for each type. Radio waves are used for Radio, Television, Microwaves, and Radar Infrared rays are used as a source of heat and to discover areas of heat differences
If most light that strikes an object passes through it, that object is _____ If some light passes through an object, but a lot of it is scattered, the object is _____. If light doesn’t pass through an object, it is _____ Transparent if most light passes through Translucent if most light is scattered Opaque if light doesn’t pass through
When light passes from one medium into another, one of these three things can happen: Light will be reflected, absorbed, or transmitted
If light is reflected, an image is formed. If the image is clear, it is a _____ reflection. If the image is fuzzy, it is a _____ reflection If the image is clear, it is a regular reflection. If the image is fuzzy, it is a diffuse reflection
When a light wave passes from one medium into another, it may be _____. If this causes you to see something that isn’t really there, it is called a _____ Refracted (bent) A mirage is a false or distorted image (light travels faster in hot air than in cool air)
Electric charge can either be _____ or _____ Like charges will _____ each other and opposite charges will _____ positive or negative like charges repel opposite charges attract
If an electrically neutral object loses electrons, its charge will be _____ If an electrically neutral object gains electrons, its charge will be _____ loses electrons: Positive gains electrons: Negative
How does the strength of the electric field around a charged particle relate to the distance from the particle? It decreases proportional to the square of the distance
The arrows showing an electric field point in the direction a _____ test charge would move. So, the arrows showing the field around a negative charge would point _____. Positive, towards the negative charge
What are the three ways that an object may be charged? Conduction Friction Induction
Electric current is a continuous flow of electric charge. Electric charge is measured in _____, and electric current is measured in _____. Conventional current moves in the direction that _____ charges would flow. electric charge: Coulombs electric current: Coulombs per second, which are Amperes (Amps) conventional current moves in the direction that positive charges would flow
Resistance is the opposition to the flow of charges in a material. Resistance is measured in _____, and depends on these three things: Ohms (Ω) Resistance depends on the material’s length, temperature, and thickness
What is Ohm’s law? For an ohmic material, if the voltage stays the same, but resistance increases, what happens to current? V=IR (voltage = current times resistance) If volts stay the same and resistance increases, current will decrease
A complete path through which charge can flow is called _____ A picture of this is called a _____ _____. If the path is broken, this is called a(n) _____ _____ circuit circuit diagram an open circuit
Explain the difference between a series and a parallel circuit. If you add another resistor to each one, what happens to the total resistance? A series circuit has resistors all in a row, one after the other. If one resistor burns out, the circuit no longer works. If you add another resistor in series, the total resistance is greater.
The regions where a magnet’s force is strongest are the: Magnetic poles
A _____ _____ surrounds a magnet and can exert magnetic forces. The direction of this is out of the ____ and into the ____ Magnetic field, out of the North pole, into the South pole
The area surrounding Earth that is influenced by Earth’s magnetic field is the _____. The angle between the directions to the geographic and magnetic poles is _____ _____. magnetosphere, magnetic declination
At an atomic level, magnetism is caused by moving _____ electrons
A region that has a very large number of atoms with aligned magnetic fields is called _____. A material that contains these is called _____ a magnetic domain, a ferromagnetic material
When orienteering (using a compass for navigation), you are cautioned against relying on it near cars, railroad tracks, or much steel. Why? Any ferromagnetic material will become a magnet if left in another magnetic field (like that of earth) for long enough. If a compass is brought near a magnet (like a filing cabinet) you can see that it has a “north” and “south” pole
How do you control the strength and direction of an electromagnet’s magnetic field? Change the current’s strength or direction
Conventional current is the flow of _____ charges. If current is flowing straight away from you, how would you describe the magnetic field around the wire? positive; the magnetic field would be clockwise around the wire
According to __________’s law, a voltage is induced in a conductor by a changing magnetic field. What is this concept used to do? Faraday’s law Used to generate electricity
Forces act on moving charges in a magnetic field. Describe the direction of the force. A charge moving in a magnetic field will be deflected in a direction perpendicular to both the magnetic field and the velocity of the charge
Created by: awallner129