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Grade 7 Science Final Exam Review Sheet
Scientific Method and Lab Safety:
The process scientists use to answer questions
-
Observations – what you notice using your 5 senses
o Examples: the balloon is blue, the water is 35oC, the road is 5 miles long, the sugar dissolved
in the water, the grass is green
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Hypothesis – a prediction about the outcome of the experiment
o Examples:

Using fertilizer will make the grass grow quicker

Heating up a substance will make it dissolve quicker
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Procedure – step by step instructions for doing the experiment
-
Inferences – a possible explanation of an observation
o Observation: the sun is shining through the window; Inference: it is morning
o Observation: the boy’s temperature is lower; Inference: he took Tylenol
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Independent Variable – the variable being tested or changed (manipulated) by the researcher
o Example – if you are testing fertilizer on grass growth, the “thing” being tested is the
fertilizer, it’s what the researcher is changing about a scenario
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Dependent Variable – the variable being measured or changed as a result of the independent
variable. Example – how high the grass grew
Scientific Method Question:
1. A student recorded the following information about a substance in a beaker
Solid blue cube, smells minty, tastes sweet
Was the student making a hypothesis, prediction, or observation?____________________________
Write an Inference for the above descriptors: _____________________________________________
__________________________________________________________________________________
Label the following as observations, inferences or hypotheses:
2. The liquid in beaker A is colorless.____________________________________________________
3. Someone is thirsty and going to drink the liquid. _________________________________________
4. The liquid in beaker A has no odor. ___________________________________________________
5. If we cool down the liquid in beaker A, it will release dissolve sugar: ____________________
6. The liquid in beaker A has an acidic pH: ____________________________________________
7. The liquid in beaker A could be apple juice: __________________________________________
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Lab Safety: Make a list next to the picture of all the things scientist is doing wrong:
Introduction to Matter and Energy Vocabulary:
1. Anything that has mass and takes up space is called _______________________.
2. The amount of matter an object contains is the object’s _____________________.
3. The amount of space an object occupies is the object’s _____________________.
4. The force of gravity on an object is the object’s ___________________________.
5. The force that exists between any two objects and keeps objects on the ground is called the force of
_______________________.
6. Length x Width x Height will determine the ________________________ of a cube.
7. Dividing the mass by the volume will tell you the object’s ______________________.
8. 150.35km would measure the _____________________ of an object or distance between two points.
9. A __________________________ property can be observed without changing what the substance is.
10. A __________________________ property can be observed only if the substance changes into a new
substance.
11. The ability to do work or cause change is ________________________________.
12. The average kinetic energy of the particles of a substance is the ________________________ of the
substance.
13. Waves are ways in which energy is _______________________________ from one place to another.
14. Energy that travels as waves is referred to as ___________________________ energy.
15. Energy transferred by the vibration of matter is ___________________ energy.
16. ____________________________ is the bouncing back of a wave when it hits a medium.
17. ____________________________ is the bending of a wave when it goes through a medium.
18. ___________________________ is when waves spread out due to a hole or edge in the medium.
19. We see color because the color wavelength _______________________ off an object and is
interpreted by our eye while all the other colors of the visible light are absorbed by the object.
Therefore a blue lunch box appears blue because blue light is _______________________ off the
lunch box and interpreted by our eyes.
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20. Everything in the universe is either matter or energy. Label the following as matter (M), energy (E) or
force (F).
a. Air
d. Water vapor
f. Gravity
i. Potential
b. Radiation
e. Crackling
g. Light
j. Friction
h. Kinetic
k. Smoke
c. Ice
sound
Density:
21. Is density a physical property or a chemical property? ____________________________________
22. What is the piece of laboratory equipment below called? __________________________________
23. It is used to measure the _______________________________________________ of a substance.
mL
mL
24. What is the volume of the hammer?
25. What is the density of the hammer if the mass is 20g?
26. Will the hammer sink or float in water, explain your answer.
27. What is the volume of the rock?
28. What is the density of the rock, if the mass is 30grams?
30. Will the rock sink or float when placed in water
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3cm
3cm
3cm
31. The diagram above is of a block of pine wood. What is the volume of the block?
32. Based on the volume you calculated above, what is the density of the block of wood if the mass is
13.5grams?
33. If the density of water is 1.0g/cm3, when placed in water the above block will
34. If the block of wood was cut into 25 pieces, the density of each individual piece of wood would be
the same, more, or less than the original cube. Explain your answer.
35. If you were to place the following liquids into the column to the right….draw in how they would
place once the solution settled based on their densities:
Maple Syrup 1.37g/mL
Water: 1g/mL
Alcohol: 0.786 g/mL
Vegetable Oil: 0.92 g/mL
36. If you dropped metal ball, with the density of 1.25g/mL, into the column above between what 2
layers would you find the ball? Draw it, in the column above.
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Phases/States of Matter:
Solids – have a definite shape and volume, particles are in a fixed position and they vibrate.
Liquid – do NOT have a definite shape, take shape of container, have a definite (fixed volume), particles
slide around but remain close together.
Gases – No Shape, No Fixed Volume, take shape and volume of container, particles are very energetic,
move very quickly and randomly, particles are very far apart.
Melting
Freezing
Evaporation
Condensing
1. Particles in the solid phase are in a ________________ position and they ____________________.
2. Particles in a liquid phase still remain ________________ together but can _________________ past
each other.
3. Particles in a gas phase are very ________________ _______________ and move around very
_____________________.
4. When the particles of a gas are cooled they move __________________ (speed) and
_________________________ together.
5. When the particles of a liquid are cooled they move __________________ (speed) and
_________________________ ________________________.
6. When the particles of a liquid are heated they move __________________ (speed) and
_________________________ ______________________.
7. When the particles of a solid are heated they move __________________ (speed) and
_________________________ ______________________.
8. Water droplets on the picture below are caused by the ______________________________(process)
of water molecules in the _____________________.
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Gas Laws
5. As the temperature on a gas increases the pressure the gas exerts on a container will
_______________________.
6. As the temperature on a gas decreases the pressure the gas exerts on a container will
_______________________.
7. As the volume of a container decreases the pressure the gas exerts on the container will
_________________________.
8. As the volume of a container increases the pressure the gas exerts on the container will
_________________________.
----------------------------------------------------------------------------------------------------------------------------------Physical vs. Chemical Properties and Changes:
Physical Properties: are properties that can be observed without changing the substances identity
Chemical Properties: are properties that can only be observed through a chemical change and will
change the identity of the substance.
Physical Change: changing a property of a substance without altering what the substance is.
A change in appearance but the substance remains the same
Chemical Change: the formation of a new substance.
1. Label the following as chemical(C) or physical properties (P):
a. Sparking
d. Can be
g. Heavy
Gemstone
hammered
h. Dull
b. Density
e. Mass
i. Volume
c. Corrosive
f. Burns
j. Explosive
k. Rusts
l. Tarnishes
Directions: If the statement is true, write “true” on the line. If that statement is false, change the
UNDERLINED word or words to make the statement true.
2. A physical property is a characteristic that can be observed without changing the substance into
another substance.
3. Sandy reaches into her locker and feels for a pencil. She identifies a pencil by its chemical
properties, including size, shape, and texture.
4. When Marshal mixes two clear liquids together a purple precipitate appears and sinks to the
bottom of the beaker. This is an indication of a physical change.
5. One physical property of wood is that is burns easily.
6. One chemical property of sodium is that it will react with chlorine and make salt.
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Directions: circle the bold word that makes the statement true
7. A physical change / chemical change does not change the identity of the substance
8. Physical changes / Chemical changes cause the creation of a new substance by changing the
identity of the reactant substances.
9. Are the following chemical changes or physical changes?
Bending an iron bar: _____________
Explosions: ___________________
Freezing apple juice: _____________
Photosynthesis: _______________
Rusting nail: ___________________
Condensing: _________________
Cutting paper: _________________
Breaking glass: ________________
Melting water: _________________
Respiration: ___________________
Corrosion on the sink: ___________
Burning wood: ________________
A rotting peach: ________________
Sublimation of CO2: ____________
Chemical Reactions are chemical changes. A new substance is created
10. When you use a catalysts the rate (speed) of the chemical reaction will ________________________.
11. Increasing the temperature will _______________________the rate of the chemical reaction.
12. Decreasing the temperature will ______________________the rate of the chemical reaction.
13. Breaking the reactants into pieces (increasing the surface area) will _______________________the
rate of the chemical reaction.
14. Increasing the concentration of reactants will _______________________the rate of the reaction.
During chemical reactions energy can be absorbed or released; endothermic or exothermic:
15. During an endothermic reactions energy is ______________________________, and the temperature
of the surroundings will ________________________________.
16. During exothermic reactions energy is _________________________________, and the temperature
of the surroundings will ________________________________.
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Atoms and the Periodic Table:
Atoms are the smallest basic unit of matter, they make up all matter
Made of 3 subatomic particles: protons, neutrons and electrons
Protons – positive charge, found in the nucleus of an atom, has mass, # located in the bottom
left corner of the symbol
Neutrons – no charge, neutral, found in the nucleus, has mass (neutrons = mass – protons)
Electrons – negative charge, surround the nucleus in energy levels, very small, very fast, have
lots of energy and no mass (same # as protons unless there is a number in the upper
right of the symbol signifying an ion).
Valence electrons are the outer most electrons in an atom (farthest from nucleus)
Mass = protons + neutrons (number located in the upper left corner of the symbol)
Atomic number = the number of protons in an atom’s nucleus, the number doesn’t change
unless the identity of the atom changes. BIG BOLD NUMBER
Ions – atoms with a charge because they have either gained electrons (become negative) or
lost electrons (become positive). There will be a +/- in the upper right of the symbol
Example Na+ (lost 1 electron)
Isotopes – atoms of the same element that have the same number of protons but a different
mass and number of neutrons.
Examples: 14C, 16C, 12C or carbon-12, carbon-14,carbon-16.
Periodic Table:
-
The periodic table is arranged by increasing atomic number
-
The metals are on the left side of the zigzag line (stair case), the non-metals are on the right
side of the zigzag line. The metalloids surround the zigzag line.
-
The periodic table is arranged into columns called groups or families and row called periods.
Elements in the same group share the most similar properties and characteristics. Elements in
the same rows show property trends.
-
Some groups on the periodic table have names:
o Group 1: Alkali Metals - most reactive metals
o Group 2: Alkaline Earth Metals – very reactive metals
o Group 17: Hallogens – most reactive non-metals
o Group 18: Nobel Gases – least reactive of all the elements, they are non-metals with a full
shell of valence electrons (8).
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Atom’s and the Periodic Table Questions:
1. Draw the Bohr’ model of the following elements
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N
Mass: _________________
Protons: ________________
Neutrons: _______________
Electrons: _______________
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S
Mass: _________________
Protons: ________________
Neutrons: _______________
Electrons: _______________
2. Nitrogen-15 and Nitrogen-14 are _____________________________ because they have a different
mass and number of neutrons.
3. ________________________ are atoms that have gained or lost electrons giving them a positive or
negative charge
4. Label the following as reactive or non-reactive
a. Nobel gases
d. Group 18
g. Group 17
b. Alkali metals
e. Halogens
h. Alkaline Earth
c. Group 2
f. Group 1
Metals
5. The ____________________ metals located in group ______ are the most reactive metals on the
periodic table.
6. The _________________________ located in group _____ are the most reactive non-metals on the
periodic table.
7. The __________________________________ located in group _____ are the least reactive elements
on the periodic table and they are _______________________________.
8. Label the following elements as metals, non-metals, or metalloids
a. Na
c. O
e. As
g. N
b. Si
d. K
f. Cu
h. Ge
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Compounds and Mixtures:
Compounds – 2 or more elements chemically bonded together. They can only be separated by chemical
reactions and creating new substances.
There are 3 major types of bonds that make up compounds:
1. Ionic – valence electrons are transferred from a metal, creating a positive ion, to a
nonmetal, creating a negative ion. The two ions are oppositely charged and attracted
to each other.
2. Covalent – valence electrons are shared between two non-metals. Sometimes those
electrons are shared equally making the bond non-polar covalent while sometimes one
atom pulls more strongly on the shared electrons making the sharing unequal, a polar
covalent bond.
3. Metallic – metal atoms equally share mobile valence electrons. Often considered a “sea of
electrons”
Mixtures – Elements and compounds are not bonded together. They are separated easily and physically
Two Types of Mixtures:
Heterogeneous Mixtures – can see the individual parts of the mixture
Solutions: Homogenous Mixtures – clear, cannot see the individual parts of the mixture.
All solutions consist of 2 parts: the solute (gets dissolved) and the solvent (what th
solute dissolves in)
Solubility – the amount of solute that a solvent can dissolve (hold) at a given
temperature
Concentration – how strong or weak the solution is (the amount of solute present)
Solutions: 3 types:
Saturated – holding the maximum amount of solute [high concentration]
Graphing – point on the line
Supersaturated – holding more than the maximum amount of solute [highest
concentration]
Graphing – point above the line
Unsaturated – holding less than the maximum amount of solute. [low
concentration or dilute]
Graphing – point below the line
Acids and Bases: Acids (H+)- turn litmus paper red, have a pH of less than 7, will neutralize a base
Bases(OH-) – turn litmus paper blue, have a pH of more than 7 and will neutralize an acid.
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Compounds and Bonds Questions:
1. The elements of a compound are ____________________________ together, whereas in a mixture
the elements are NOT _______________________ allowing them to be separated easily.
2. Label the following descriptions as compounds or mixtures
a. Elements can be separated by filter: _____________________________
b. Elements are not in fixed proportions: ____________________________
c. Elements are bonded: ______________________________________
d. Element can be separated only by a chemical reaction: __________________
e. Elements are NOT bonded: ________________________________________
f. Elements are separated by physical means: __________________________
3. Label the following as ionic (I), covalent (C), or metallic (M) metallic.
a. Metal + Nonmetal _______________________
b. Nonmetal + Nonmetal _____________________
c. Only metal atoms _________________________
d. Electrons are transferred____________________
e. Electrons are mobile and free to move around ___________________________
f. Electrons are shared___________________________
g. Bond between a negative and a positively charged ion _____________________
4. Which of the following substances is a compound and explain how you know: Na, HF, Ge, Ra
_______________________________________________________________________________________
Chemical Formulas:
9. How many different types (kinds) of elements are present in K2SO3? ________
10. How many potassium (K) atoms are present in K2SO3? ________
11. How many Sulfur atoms are present in K2SO3? ________
12. How many Oxygen atoms are present in K2SO3? ________
13. What is the total number of atoms present in K2SO3? ________
Acid/Base Questions:
14. If lemon juice has a ph of 4 is it an acid or a base? _______________________________
15. If bleach has a pH of 14 is it an acid or base? __________________________________
16. What pH does a substance needs to be neutral? _________________________________
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Mixtures and Solutions Questions:
Use the diagram below to answer the following questions
A student dissolves sugar into water….
100ml H2O
50g sugar
100ml H2O
35g sugar
100ml H2O
25g sugar
100ml H2O
15g sugar
17. Circle the box above that is most dilute. Put a square around the one that is the most concentrated.
18. What is the solute? ________________________________________
19. What is the solvent? _______________________________________
20. You dissolve 50 grams of salt into 300mL of water to create a salt water solution
a. What is the solute? _________________________________
b. What is the solvent? ________________________________
Use the graph below to answer the following questions
14. What is the solubility of substance A at 40oC?
15. What is the solubility of substance C at 90oC?
16. What happens to the solubility of substance B as
the temperature increases?
17. What happens to the solubility of substance A as
the temperature decreases?
18. What happens to the solubility of substance C as
the temperature decreases?
19. Which of the following substances could be a gas?
Explain how you know.
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Energy: Is the ability to do work or cause change
Energy Sources: where the energy comes from
Renewable: not in a limited supply, can replenish itself. Ex: solar, wind, hydropower
Nonrewable: in a limited supply, cannot replenish itself. Ex: fossil fuels (oil, coal and natural
gas) and nuclear energy
Potential Energy – energy that is stored based on the object’s positions or chemical composition.
Gravitation Potential Energy – energy depends on location, highest point most PE
Chemical Potential Energy – energy stored in the bonds of compounds.
Energy stored in fossil fuels and in the food we eat
Elastic Potential Energy – energy stored in the stretching of a material (rubber band)
Kinetic Energy – energy of motion
Sound Energy – energy traveling through the vibrations of an object’s particles
Radiation – light, energy traveling as an electromagnetic waves
Questions:
1. The ability to do work or cause change is _________________________.
2. The Law of Conservation of Energy states that energy is never ___________________ or
________________________ it only _______________________ into another form.
3. When a rock falls off a cliff, potential energy changes into ___________________________.
4. When a pendulum swings back and forth its kinetic energy changes into _______________________
energy when it swings back upwards.
5. Energy caused by the vibrations of a substance’s particles is _______________________ energy.
6. __________________________ ________________________ is the energy of motion.
7. ___________________________ ____________________ is energy that is stored based on an
object’s ____________________________ or _______________________ ____________________
8. Energy resources that are in limited supply are called ______________________________, while
energy sources not in a limited supply are called __________________________________.
9. Label the following as Renewable or Non-Renewable
Wind: ______________________ Hydroelectric: ________________
Coal: _______________________Geothermal: __________________
Nuclear: ____________________ Solar: _______________________
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10. Label the following as examples of kinetic or potential energy
a. A bicycle sitting in the drive way
b. A car stopped at a red light
c. A sky diver in free fall
d. A car parked at the drive in
e. An apple falling off a tree
f. A rock on a cliff
g. A runner in the middle of a race
h. A dog chasing a cat
Use the diagram to answer the following questions…….
11. The roller coaster’s speed is ________________________ from point W to X and from point Y to Z.
This means that the roller coaster is ___________________________ because its speed is changing.
12. At which point is the roller coaster the farthest from the ground? _____________________
13. At which point does the roller coaster have the maximum gravitation potential energy? _________
14. At which point is the roller coaster moving the fastest? ______________
15. At which point does the roller coaster have the greatest kinetic energy? ________
16. Is all the kinetic energy transferred into potential energy as the roller coaster travels from point X to
point Y? Explain your answer.
_________________________________________________________________________________
_________________________________________________________________________________
17. What force is slowing down the roller coaster throughout its journey? _______________________
18. Gravitational potential energy is maximum when the object is at its ________________________
position off the ground.
19. Why does the roller coaster have more gravitational potential energy at point W than point Y?
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Heat and Temperature:
Heat - the flow of energy from a substance at a higher temperature to a substance at a lower temperature.
Temperature – the average kinetic energy of a substance’s particles
Insulators – are substances that do not transfer heat and energy easily, block heat/energy flow
Conductors – are substances that transfer heat and energy easily (METALS), promote heat/energy flow
Heat is transferred in 3 ways:
1. Conduction – the flow of heat through objects that are in direct contact (touching)
2. Convection – the flow of heat in liquids and gases based on differences in densities
3. Radiation – the flow of heat as an electromagnetic wave (light, ultraviolet, gamma, radio etc.)
Questions:
1. The average kinetic energy of the particles of a substance is the ________________________ of the
substance.
2. A substance the reduces the flow of heat is referred to as an ________________________________.
3. A substance in which energy flows easily is referred to as a _______________________________.
4. Label the following as conductors or insulators:
Silver cup: __________________
Plastic Fork: ________________
Copper wire: ________________
Tin: _______________________
Rubber band ________________
Wooden Spoon: _____________
Styrofoam cooler: _____________
Fabric: ______________________
Gold bar: ____________________
Mercury: ____________________
5. Heat always flows to an object that has a _____________________________ temperature.
6. Conduction occurs when temperature differences exists between object that are ________________.
7. Convection occurs in _______________________ and ______________________ based on
differences is _______________________, caused by temperature differences.
8. Energy as heat always flows from a _______________temp. to a ___________________ temp.
9. Temperature is measured in _____________________. (unit for temperature not a temp. scale)
10. You can feel the heat from a fire without touching the fire because its transferred by waves through a
heat transfer known as _____________________________.
11. Steel joints often separate sections of concrete on bridges because ____________________________
_________________________________ can cause the concrete to get bigger and crack.
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Motion, Forces and Simple Machines
Key Ideas:
1. Energy and Matter interact through forces that result in changes in motion
2. Machines make work easier by changing the magnitude and direction of the forces
Motion – when the distance between 2 objects changes
Reference Point (frame of reference) – needed to determine if an object’s position has changed.
Forces: a push or a pull on an object
Balanced forces – will not change the motion, net force = 0
Unbalanced forces – change the motion, net force is greater than 0
Forces in the same direction are added, Forces in opposite directions are subtracted
Net Force – total amount of force acting on an object
Friction – forces between any 2 surfaces, opposes motion, always in the opposite
direction of motion
Gravity – a force of attraction between all bodies of matter. It is a pulling force toward
the center of the earth.
Newton’s 3 Laws of Motion:
1. Inertia: An object at rest will remain and rest and an object in motion will remain in motion
until an unbalanced force is acted upon it.
Inertia – an object’s resistance to a change in motion.
2. Force = mass x acceleration
When you increase the force, the acceleration increases
When you increase the mass, the acceleration decreases
3. For every action there is an equal and opposition reaction
Momentum = mass x velocity, momentum is conserved and transferred
Measuring Motion
Distance – the length between any two points along the path of an object
Speed – is the distance an object travels in a given amount of time (how fast)
Constant Speed – moving at the same speed, not speeding up or slowing down, shown by a
straight line on a distance versus time graph. Horizontal line’s show no motion.
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Velocity – speed in a given direction (vector quantity)
To calculate velocity:
Velocity = Distance/time + direction
Acceleration – the rate at which the velocity is changing (speed or direction change)
To calculate acceleration:
Acceleration =
Final Velocity (Vf) – Initial Velocity (Vi)
Time
Machine – a device that allows work to be done and offers an advantage to the user (makes
work easier by changing the amount or direction of the force needed to do the work)
There are six types of simple machines: lever, pulley, wheel and axel, screw,
incline plane, wedge,
1. ____________________________ is the change of position over time.
2. A force that can change the motion of an object is called a(n) ______________________ force.
3. The overall force acting on an object when all forces are combined is called ______________.
4. _________________________________ forces will NOT change the motion of an object and
have a net force of zero.
5. _____________________ resists motion between any two surfaces
6. Newton’s 1st law of motion states that an object at rest will remain at rest, and an object in
motion will remain in motion until an unbalanced force acts upon it.
Calculate the net for on each of the boxes below and determine if the boxes motion will change
and in what direction.
3
3
A.
C.
7
2
13
B.
9
=
D.
8
9
13
1
4
5
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7. Newton’s third law of motion states that for every action _______________________________
__________________________________________________.
8. What is the equation for Newton’s 2nd law? ________________________________________.
9. A car rolls down the hill and hits some traffic cones before stopping. What happens to the
momentum of the car as it hits the traffic cones?
A.
B.
C.
D.
Some of the car’s momentum is transferred to the traffic cones.
All of the car’s momentum is transferred to the traffic cones.
None of the car’s momentum is transferred to the traffic cones.
The traffic cones stop the car from rolling farther
10. What is velocity? _______________________ in a given__________________________.
11. List the 6 simple machines and give 2 common examples of those machines.
Simple Machine
Example (2)
12. Simple machines like levers, axes, and inclined planes make work easier because they change
the ________________________ and the ________________________ of the force.
13. A knife is used to cut meat. The metal part cuts through the meat, pushing it apart into two
smaller sections. Which simple machine is a knife?
14. Use the graph below to answer the following questions:
a) How far has the person traveled after 3mins?
b) Did the person’s speed change in the first 4 minutes?
c) Calculate the person’s speed for the first 4 minutes?
d) What happened at minute 4? How long did it last?
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