Physics Test 11/4
Aristotle time definition
"the calculable measure of motion with respect to before and afterness."
physics
-Branch of science that involves the study of the physical world: energy, matter and how they are related. - study of energy and matter
distance
-The length of the path between to points. The path can be a curved distance -measure of space between 2 points
dependent variable
-The variable in an experiment that changes in response to the choices made by the experimenter - The variable in the experiment that is measured as the output of the experiment
Energy
-the capacity to do work - A measure of a system's ability to change or to create change in other systems
List the steps of the scientific method.
1. Observation 2. Hypothesis 3. Prediction 4. Experiment 5. Analyse Data 6. Conclustion
Summarize the four steps for solving physics problems mentioned in the text.
1. identify what the problem is asking for 2. identify the information you're given 3. identify relationships you are given 4. combine the relationships with what you know to find what you're asked for
Your friend rides her bicycle across town at a constant speed. Describe how you could determine her speed.
1. measure the total distance traveled 2. find out the total time it takes to travel that distance 3. then divide the distance by time
Summarize how to make a graph by listing the steps you would follow.
1. x-axis with Label, Units, and unit interval marks 2. y-axis with Label, Units, and unit interval marks 3. Title of graph 4. Data = Points on the graph, or line, or some curve 5. Legend explaining the multiple curves 6. Citation for source of data
Order the following lengths from shortest to longest. a. 400 millimeters b. 22 kilometers c. 170 meters d. 3.3 centimeters
22 kilometers> 170 meters> 400mm > 3.3cm
second
A basic unit of time in both the English and SI systems of measurement
system
A collection of related factors that you identify to help answer a question or solve a problem
variable
A factor or quantity that affects the result of an experiment and which can have different values under different conditions
ratio
A fraction; a math expression that relates the magnitude of quantities relative to each other.
line of best fit
A line through a scatter plot of data points that best expresses the relationship between those points.... or ... A straight line that estimates a relationship between independent and dependent variables.
length
A measured distance that uses a specific measurement system's units
Scientific Method
A process of learning that begins with a hypothesis and proceeds to prove or change a hypothesis by comparing the hypothesis to scientific evidence determined by experimental measurements
natural law
A rule that describes an action (or set of actions) and the results in the universe
theory
A scientific explanation supported by a collection of evidence collected over a long period time
Define the term system as it relates to experiments.
A system is a group of objects, effects, and variables that are related.
closed system
A system where the amount of matter (i.e. mass) is constant and does not change. Energy may be added to taken away
isolated system
A system where the amount of matter and energy remain constant. No mass or energy are added or removed
control variable
A variable that is kept constant during a controlled experiment.
experiement
An event created to test or investigate a hypothesis
List and define the two categories we use to classify everything in the universe.
Everything in the universe is classified as either matter or energy. Matter is all of the "stuff" in the universe that has mass and takes up space. Energy is the measure of the ability to make things change.
A hypothesis is a random guess. True or false? Explain your answer.
False; A hypothesis is an educated guess because it is based off of prior research
Give an example of a quantity that is often measured in metric units and a quantity that is often measured in English units.
Grams are often used on nutrition facts labels. Miles are commonly used to indicate the distance between two cities in the United States. Liters are used to measure cola. Gallons are used to measure gasoline.
You wish to do an experiment to determine how a ball's radius affects how fast it rolls down a ramp. List the independent and dependent variables in this experiment.
Independent variable: radius of the ball Dependent variables: angle of the ramp, initial speed, mass of the ball, internal structure (hollow or solid), starting position, condition of the ramps surface.
SI
International System of Units (SI) used by most countries for everyday measurement and used by the scientific community worldwide
Is light matter? Why or why not?
Light is not matter because it doesn't take up any space and does not have a mass
Measurements are precise values that are repeatable using agreed upon standards 5 characteristics:
Magnitude Units Accuracy Precision Direction (for Vectors)
What property does matter have that energy does not?
Matter has mass and takes up space
How have physicists come to understand the natural laws?
Physicists use experiments and analysis to better understand natural laws. Natural laws are developed and refined as more information is discovered.
Repeatable
The ability of measuring experimental evidence that can be seen independently by others if they perform the same experiment or observation in the same way
precision
The characteristic of a measurement that describes how close together and reproducible repeated measurements are
Domain
The length of the path between to points. The path can be a curved distance
english system
The measurement system used by people in the United States of America
Instantneous speed
The rate of change of distance (A speed measurement) during an extremely small time interval.
independent variable
The variable in an experiment that is changed (i.e. manipulated) by the experimenter and that causes changes in the dependent variable in the experiment
macroscopic
When an item is measured on a larger scale, i.e. when zoom is from far away.
Explain the main difference between the macroscopic scale and the atomic scale.
a macroscopic scale can be seen and measured directly. An atomic scale is far too small to observe directly, but can give an understanding of the behavior of atoms and molecules.
time interval
a quantity of time separating two events, the duration of time between the starting and ending times
Hypothesis
a tentative statement that can be tested by comparison with scientific evidence
Convert: a. 3 minutes = ___ seconds b. 200 seconds = ___ minutes, ___ seconds c. 2 days = ___ minutes d. 1,000 minutes = ___ hours
a. 180 b. 3min and 20 sec c. 2880 d. 16 hours and 20 min
Convert: a. 3 kilometers = ___ meters b. 1.5 meters = ___ centimeters c. 110 centimeters = ___ meters d. 2.5 centimeters = ___ millimeters
a. 3000 b. 150 c. 1.1 d. 0.025
State whether you would measure each quantity in kilometers, meters, centimeters, or millimeters. a. The length of a car b. A single grain of rice c. The thickness of your textbook d. The distance from your house to school
a. meters b. millimeters c. centimeters d. kilometers
You wish to make a graph of the height of the moon above the horizon every 15 minutes between 9:00 p.m. and 3:00 am during one night. a. What is the independent variable? b. What is the dependent variable? c. On which axis should you graph each variable?
a. time b. height of the moon c. time on the x-axis, angular position on the y-axis
constant speed
an unchanging speed of a moving object that covers the same distance each second
Why is it important to understand both English and metric units?
because units allow people to communicate amounts uniformly in a way that can be understood by others; you need to be able to comprehend what other what other mean
The delta sign means (Δ)
change
A car traveling the same distance every second is moving at ____.
constant speed
What do you call variables that are kept the same in an experiment?
control variable
A mouse is moving in a straight line at a steady speed of 2 m/sec for 10 seconds. How far (in meters) did the mouse travel?
d = v × t = (2 m/sec)(10 sec) = 20 meters
If it takes 500 seconds for the light from the sun to reach Earth, what is the distance to the sun in meters? (The speed of light is 300,000,000 meters/second).
d = v × t = (300,000,000 m/sec)(500 sec) = 150,000,000,000 meters d = 1.5 × 1011 meters
The ____ variable goes with the y-axis of a graph.
dependent
Light ____ have mass
does not
The ____ uses length measurements of inches, feet, yards and miles.
english system
A(n) ____ can help you understand the natural laws that relate matter and energy.
experiment
A variable in an experiment that is changed by the experimenter at the start of each run of the experiment
experimental value
Accuracy
how close a measurement is to the true value
When you formulate a(n) ____, you make an educated guess or prediction that can be tested by an experiment.
hypothesis
You want to find out whether the birds near your school prefer thistle seed or sunflower seed. You have a bag of thistle seed, a bag of sunflower seed, and two bird feeders. Describe the experiment you would do to see which type of seed birds prefer. Write down your question, your hypothesis, and the procedure you would follow when doing your experiment.
hypothesis : the birds prefer sunflower seeds procedure: fill two bowls one with sunflower and one with thistle seeds and wait 7 days to see which one has less.conclusion ; the bowl with the least amount of seeds is the more liked seed.
Distance is measured in units of ____.
length
Air has
mass
_____ is the measure of the amount of matter in an object.
mass
significant digits
meaningful digits in a measured quantity that can be verified by repeating the experiment
The ____ uses length measurements of millimeters, centimeters, meters, and kilometers.
metric system
____ properties are too small to be directly observed.
microscopic
It is believed all events in nature obey a set of ____ that do not change.
natural laws
range
output values from a function, or output values for the dependent variable
In physics, time is usually measured in units of ____.
seconds
____ is the distance traveled divided by the time taken.
speed
Write the form of the speed equation that you would use in each of the following scenarios. Let v = speed, t = time, and d = distance: a. You know distance and speed and want to find the time. b. You know time and distance and want to find the speed. c. You know speed and time and want to find the distance.
speed= distance/ time time= distance/ speed distance = speed x time
you are doing an experiment to determine whether a dropped balls mass affects the rate at which it falls. Describe the system you are studying. Write down your question hypothesis and the procedure you would follow when you're doing the experiment .
system: balls of different mass, earth and the air question; does the mass of the ball affect the rate at which it falls hypothesis ; the mass of the ball does not effect the rate at which the ball falls procedure: get different balls with different masses and recored the time it takes for the balls to drop conclusion; similar times it takes for the ball to drop indicates mass does not effect the rate at which it takes to drop
A bicyclist, traveling at 22 miles per hour, rides a total of 44 miles. How much time (in hours) did it take?
t = d ÷ v = (44 miles) ÷ (22 miles/hr) t = 2 hours
mass
the amount of matter in an object
objective
the considering evidence that documents only what actually happens and is observed as exactly as possible
analysis
the detailed thinking you do to interpret and understand what you observe
time
the duration, or interval, between start and finish
speed
the rate at which an objects's distance changes over time, Rate of change of distance
Why is it important to only change one experimental variable at a time in an experiment?
the results can be directly attributed to the independent variable
Resolution
the smallest interval that can be measured
A quantity of time is known as a(n) ____.
time interval
What are the two different meanings of the word time?
time interval and precise time
Why are units important when measuring quantities?
to be precise
average speed
total distance divided by total time
m/sec, km/h, mi/h or mph, cm/s, ft/min
units of speed
It takes Brooke 10 minutes to run 1 mile. What is her speed in miles per minute?
v = d ÷ t = 1 mile ÷ 10 min = 0.1 miles/min
The gray wolf is a threatened animal that is native to the United States. A wildlife biologist tracks a gray wolf that moves 250 meters in 100 seconds. Calculate the wolf's speed in meters per second.
v = d ÷ t = 250 m ÷ 100 sec = 2.5 m/sec
On a Position-time Graph, what is the x and y variable
y: positon x: time
What is the speed of an object that is standing still?
zero
