Download Extra revision sheet quarter 2 Physical science Grade 9

Extra revision sheet quarter 2
Physical science
Grade 9
Chapter 9—Nuclear Changes
MULTIPLE CHOICE
1. Radioactive materials have unstable
a. electrons.
c. protons.
b. nuclei.
d. neutrons.
2. After the nucleus of a radioactive element undergoes changes, the element can
transform into
a. a different isotope of the same element.
b. an entirely different element.
c. Both (a) and (b)
d. Neither (a) nor (b)
3. Alpha particles
a. are positively charged.
b. consist of two protons and four neutrons.
c. can penetrate any thickness of matter.
d. All of the above
4. Which of the following is not a type of nuclear radiation?
a. alpha particles
c. neutron emission
b. beta particles
d. X rays
5. The type of nuclear radiation that can penetrate farthest through matter is called
a. radons.
c. neutron emission.
b. gamma rays.
d. X rays.
6. The process of nuclear change in an atom of radioactive material is called
a. nuclear decay.
c. nuclear mass.
b. isotopes.
d. radon.
7. Nuclear radiation refers to charged particles or energy emitted by an unstable
a. proton.
c. nucleus.
b. atom.
d. isotope.
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8. In alpha decay, the mass number of the atom before the decay
a. equals the sum of the mass numbers of the products.
b. does not change after the decay.
c. is the same as the atomic number.
d. cannot be determined.
9. Alpha particles are nuclei of
a. oxygen.
c. helium.
b. nitrogen.
d. radium.
10. As beta particles ionize they
a. lose energy.
c . neither lose nor gain energy.
b. gain energy.
d. None of the above
11. During beta decay, a nucleus
a. gives up two protons and two neutrons.
b. maintains the same number of protons and neutrons.
c. loses a proton and gains a neutron.
d. gains a proton and loses a neutron.
12. When a nucleus undergoes nuclear decay by gamma rays, the atomic number of
the element
a. remains the same.
c. decreases by one.
b. increases by one.
d. increases by two.
13. In radioactive decay, with each successive half-life, half the remaining sample
decays to form another
a. nucleus.
c. life-form.
b. element.
d. proton.
14. The attractive force between protons and neutrons in a nucleus caused by the
strong nuclear force acts only
a. outside the nucleus.
c. only in unstable isotopes.
b. over a very short distance.
d. intermittently.
15. Nuclei with too many or too few neutrons are
a. never found.
c. unnatural.
b. unstable.
d. stable.
16. The process of the production of lighter nuclei from heavier nuclei is called
a. mass energy.
c. magneticism.
b. fusion.
d. fission.
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17. Fusion occurs when nuclei
a. split.
c. mutate.
b. combine.
d. gain energy.
18. The opposite reaction to fusion is called
a. beta decay.
c. fission.
b. alpha decay.
d. neutron transmission.
19. In the equation E = mc2, “c” stands for
a. carbon.
c. the speed of light.
b. the total energy.
d. the size of the particle.
20. A fission chain reaction can be slowed by using materials that will
a. absorb some of the neutrons.
b. convert some of the neutrons to protons.
c. increase the rate of the neutron multiplication.
d. decrease the amount of available oxygen in the air.
21. Background radiation can come from
a. the sun.
c. plants.
b. water.
d. All of the above
22. Radon gas is produced
a. by smoking cigarettes.
b. in nuclear power plants.
c. through radioactive decay of uranium-238 in Earth’s crust.
d. as a result of rotting wood in the basements of houses.
23. Small radioactive sources that are present in smoke detectors release
a. alpha particles.
c. gamma rays.
b. beta particles.
d. neutrons.
24. Short-lived isotopes used in agriculture to monitor water flow through crops are
called
a. trace elements.
c. carbon tracers.
b. radioactive tracers.
d. alpha-emitting isotopes.
25. The particles that are released by the radioactive sources in smoke alarms have
charge and produce a(n)
a. odor.
c. electric current.
b. beam of light.
d. sound.
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26. Radioactive tracers are short-lived
a. drugs.
c. tumors.
b. isotopes.
d. rays.
27. To treat certain brain tumors, doctors can use small beams of _____ that are
focused to kill only the tumor cells.
a. X rays
c. alpha rays
b. beta rays
d. gamma rays
28. The use of nuclear reactors to generate electricity is
a. decreasing rapidly.
c. found in dozens of countries.
b. found only in the United States.
d. totally safe.
29. The ideal location for a radioactive-waste storage facility is one that is
a. in a sparsely populated area.
c. far away from ground water.
b. in an area free from earthquakes.
d. All of the above
30. When a fusion reactor for safely generating energy is developed, the element that
could meet Earth’s
energy demands for millions of years is
a. oxygen.
c. hydrogen.
b. nitrogen.
d. lithium.
COMPLETION
1. Nuclei with more than 83 protons are always unstable, no matter how many
____________________ they have.
2. The ability to create a chain reaction depends on the number of
____________________ released.
SHORT ANSWER
1. What are massive, positively charged particles emitted by some radioactive
elements?
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2. What is the energy and matter released by radon gas that causes health concerns
called?
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3. If the atomic number of an atom before alpha decay is 88, and one of its products
has an atomic number of 86, what is the atomic number of the second product?
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5. What type of particle is emitted when carbon-14 decays into nitrogen-14?
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6. What is the time required for half a sample of radioactive nuclei to decay called?
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7. After three half-lives, what fraction of the original radioactive element remains?
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8. To determine the age of fairly recent remains (in the tens of thousands of years as
opposed to millions of years), scientists compare the ratio of what two elements?
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9. What is the force that binds protons and neutrons together in a nucleus called?
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10. The protons in a nucleus both repel and attract each other. In stable nuclei, which
are stronger, the attractions or the repulsions?
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11. The equivalence of mass and energy means that matter can be converted into
energy and energy into matter. Write the equation that expresses this equivalence.
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12. What is the process by which a nucleus splits into two or more smaller fragments,
releasing neutrons and energy, called?
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13. What is the name for the process in which light nuclei combine at extremely high
temperatures, forming heavier nuclei and releasing energy?
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14. According to the theory of relativity, what does mass times the speed of light
squared equal?
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15. In the equation, E = mc2, what does the E stand for?...............................................
16. In the equation, E = mc2, what does the m stand for?...............................................
17. In the equation, E=mc2, what does c stand for?......................................................
18. Name one good use of the energy produced in a controlled chain reaction.
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19. What is nuclear radiation that is emitted from natural sources all around us called?
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20. Ionization occurs when atoms lose or gain what?
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21. What type of nuclear radiation can travel farthest through matter?
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ESSAY
1. All four types of nuclear radiation have just been released simultaneously and are
headed your way. Which will arrive first, which will have the greatest potential to
cause damage to your tissues, and what can you do to protect yourself against each?
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2. A beta particle is negatively charged, but it comes from a positively charged
nucleus. How is this possible?
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3. Name at least two disadvantages of a nuclear-fission reactor.
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Chapter 10—Motion
MULTIPLE CHOICE
1. The distance traveled by an object divided by the time it takes to travel that
distance is called
a. average velocity.
c. average acceleration.
b. average speed.
d. activity.
2. In order to determine speed, you must know
a. time.
c. Both (a) and (b)
b. distance.
d. None of the above
3. What is the speed of an object at rest?
a. 15 km/h
b. 0 km/h
c. 1 km/h
d. This cannot be determined without further information.
4. The difference between speed and velocity is that velocity includes
a. direction.
c. time.
b. distance.
d. weight.
5. An airplane is flying at 635 km per hour at an altitude of 35 000 m. It is currently
over Kansas and is approximately 16 minutes ahead of its scheduled arrival time.
What is its velocity?
a. 635 km/h
b. 16 m/min
c. 35 000 m/s
d. This cannot be determined without further information about its direction.
6. Which of the following does not indicate velocity?
a. 14 m/s SSE
b. 40 km/h toward the town square along the main street
c. 80 km/h going from New York toward New Jersey
d. 28 km from Los Angeles to Catalina Island
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7. Acceleration is defined as the change in velocity divided by
a. speed.
c. time.
b. final velocity.
d. distance.
8. The SI unit for acceleration is
a. mph.
c. m/s2.
b. ft/s2.
d. v / t.
9. On a velocity-time graph, a line with a negative slope indicates that the object is
a. speeding up.
b. slowing down.
c. not moving.
d. traveling at a constant speed.
10. When the velocity of an object changes, it is acted upon by a(n)
a. force.
c. momentum.
b. inertia.
d. deceleration.
11. The combination of all of the forces acting on an object is called the
a. total force.
c. super force.
b. union of forces.
d. net force.
12. If the net force acting on a stationary object is zero, then the object will
a. accelerate in the direction of the strongest force.
b. remain at rest.
c. begin moving backwards.
d. decelerate at a steady rate of speed.
13. If the net force on an object is zero then the object has
a. reaction forces.
c. balanced forces.
b. action forces.
d. unbalanced forces.
14. A tug-of-war that results in one team pulling the other across the line is an
example of
a. action forces.
b. reaction forces.
c. balanced forces.
d. unbalanced forces.
15. Which of the following best illustrates balanced forces?
a. a rock falling to the ground
b. a stretched rubber band being held between two hands
c. a person lifting a heavy box off of the ground
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d. a crash between a large truck and a train
16. Friction is defined as
a. force that opposes motion between two surfaces that are touching.
b. rate at which velocity changes.
c. resistance of an object to a change in its velocity.
d. speed of an object in a particular direction.
17. A force is continuously applied to an object, causing it to accelerate. After a
period of time, however,
the object stops accelerating. What conclusion can be drawn?
a. The mass of the object has increased.
b. Gravity on the object has increased.
c. The object is experiencing some kind of friction.
d. The momentum of the object has reached a maximum.
18. Which of the following situations best demonstrates the effects of friction?
a. a parachutist descending to the ground
c. an apple falling from a tree
b. a loaded slingshot
d. two trucks colliding
19. Which of the following statements is true?
a. Frictional forces are greatest when both surfaces are rough.
b. When a truck is parked on a hill, friction pulls the truck down the hill.
c. Air resistance always opposes friction.
d. Friction can exist between two objects even when they are not in contact.
20. An object is in motion when
a. you observe the object move.
b. the object’s speed increases.
c. the object’s displacement is greater than the distance traveled.
d. the object changes position relative to a stationary reference point.
21. Which of the following is a displacement?
a. 5 m/s
c. 0.7 m/s2
b. 10 ft
d.3 blocks east
22. Which is an example of kinetic friction?
a. friction between a car’s windshield and the air as you drive into the wind
b. friction between your shoes and the ground when you stand still
c. friction between a sticky note and the page of a book as it marks your place
d. friction between your skin and a pencil as it rests in your palm
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23. If the slope of a line on a distance-time graph is 1, the speed of the object being
plotted is
a. constant.
c. increasing.
b. 0.
d. decreasing.
24. Which straight-line acceleration indicates an increase in speed?
a. 0 m/s2
b. 15 m/s2
c. 4 m/s2
d. All of the above
25. Which of the following speeds is the most accurate?
a. 100 miles per day
c. 100 miles per minute
b. 100 miles per hour
d. 100 miles per second
26. How can the friction on a water slide be reduced?
a. warm the surface of the slide
b. keep the surface of the slide dry
c. run a constant stream of water down the slide
d. increase the slope of the slide
27. Which is an example of balanced forces acting on an object?
a. a kangaroo jumping
c. a cyclist slowing down
b. a car turning a corner
d. a leaf lying on the grass
28. A car is parked on a hill. In order to keep the car from rolling downhill, how great
must the static friction acting on the car be?
a. equal to the force pulling the car downhill
b. greater than the force pulling the car downhill
c. greater than the force pulling the car uphill
d. smaller than the force pulling the car uphill
COMPLETION
1. When an object covers equal distances in equal amounts of time, it is moving at
a(n) ____________________ speed.
2. Velocity describes both speed and ____________________.
3. Because the speed of an object can change from one instant to the next, dividing the
total distance covered by the time of travel gives ____________________.
4. When an object is seen moving in relation to a stationary object, the stationary
object is called ____________________.
5. Acceleration is the rate at which ____________________ changes.
6. When a car skids on a wet road, it is called ____________________.
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7. On a distance-time graph, distance is usually the ____________________ variable.
8. Acceleration can be determined from a velocity-time graph by calculating the
____________________.
9. The friction between a book at rest and the desk it is lying on is an example of
____________________ friction.
10. The distance-time graph for a faster moving object has a(n)
____________________ slope than the graph for a slower moving object.
11. You observe that a car is in motion when it changes ____________________
relative to a reference point.
12. Force is a quantity made up of magnitude and ____________________.
13. If a cyclist moves at a constant speed of 5.1 m/s, he travels a distance of
____________________
every second.
14. On a distance-time graph, time is usually the ____________________ variable.
15. The friction between the bristles of your toothbrush and the surfaces of your teeth
is an example of ____________________ friction.
16. Displacement is the change in ____________________ of an object.
17. The measurement 82 km/h southeast is a measurement of
____________________
18. If you are riding on a northbound train and you walk southbound down the aisle,
your ____________________ velocity is less than the velocity of the train.
19. A person on a skateboard accelerates at a rate of 1.5 m/s2. This rate means that
she is moving 1.5 meters ____________________ .
20. The rotating propeller of an airplane is an example of ____________________
acceleration.
21. The symbol v represents ____________________.
22. When the pilot of an airliner raises its flaps to slow down, the plane’s acceleration
is ____________________ the direction of motion.
23. A birdfeeder hanging from the branch of a tree does not move up or down because
there is a tension force pulling up on the feeder that ____________________ the
force of gravity pulling the feeder down.
24. If you push a desk westward and your friend pushes northward on the desk with
equal force, the desk will move in a ____________________ direction.
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SHORT ANSWER
1. Rearrange the speed equation to isolate time on the left side of the equation.
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2. If an object traveling in one direction has a positive velocity, what kind of velocity
would the same object traveling in the opposite direction have?
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3. Define velocity in terms of displacement.
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4. In your own words, explain the similarities and differences between velocity and
acceleration.
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5. Explain why a cyclist accelerates when turning a corner even if her speed doesn’t
change.
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6. Two archers shoot identical arrows at a target from exactly opposite directions. Use
your knowledge of net forces to describe the movement of the target.
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7. Distinguish between balanced forces and unbalanced forces.
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8. What will the result be if two equal forces act on a single object from different
directions that are not exactly opposite?
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9. Why is it easier to push a crate over a smooth concrete sidewalk than over grass?
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10. List two situations in which friction is helpful or necessary.
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11. If a car travels down the highway at a constant speed, are the forces acting on the
car balanced or unbalanced? Explain.
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12. What are the two main types of friction? Give an example of each type.
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13. Under which condition would a car experience more friction: when it is on a
clean, smooth surface, or when it is on a road covered with gravel? Explain.
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14. Is the friction between car tires and pavement greater when the car is at rest or in
motion? Explain.
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15. Develop an equation to find the average velocity of an object, when you are given
the object’s initial (vi) and final (vf) velocity.
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16. A Transair plane is flying east at 275 km/h. A World air plane is flying west at
275 km/h. Are the two planes flying at the same velocity? Explain your answer.
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PROBLEM
1. During a race, a sprinter increases from 5.0 m/s to 7.5 m/s over a period of 1.25 s.
What is the sprinter’s average acceleration during this period?
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2. The winning time for a 500.0 mile circular race track was 3 hours and 13 minutes.
What was the driver’s average speed? What was the driver’s average velocity?
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3. A plane is flying due east in still air at 395 km/h. Suddenly, the plane is hit by wind
blowing at 55 km/h toward the west. What is the resultant velocity of the plane?
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4. A car moving at a speed of 20 m/s accelerates at a rate of –4 m/s2 to a complete
stop. How long does it take the car to stop?
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5. A car travels along a straight road at 65 km/h when it begins to pass a train
traveling on a track parallel to the road. The train is moving at 35 km/h in the same
direction as the car. If the train is 150 m long, how many seconds will it take for the
car to pass the train?
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6. A boat moves at a speed of 15 km/h in still water. The river it is traveling in flows
at a rate of 3 km/h downstream. What is the velocity of the boat if it travels
downstream? What is the velocity of the boat if it travels upstream?
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ESSAY
1. A child throws a ball up in the air to a height of 3.5 m and catches it at the same
point from which he threw it. The ball is in the air for a total of 1.7 s. What is the
average velocity of the ball? Explain your answer.
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2. It is often recommended that motorists carry a heavy bag of sand in the trunk of
their car when driving on slippery roads. Use the concept of friction to explain why
this would be helpful.
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