Download Grade 6 Physical Posttest

Grade 6 Physical Posttest
Select the best answer to each question.
____
1. Which of these is an example of the conversion of kinetic energy into gravitational potential energy?
A. a bicyclist coasting down a long hill
B. a car engine moving the car forward
C. a roller coaster car moving toward the top of a rise in the tracks
D. a thrown ball falling toward the ground after passing through the top part of its motion
____
2. A ball is tossed into the air.
Which of the following statements about the ball is the best example of the Law of Conservation of Energy?
A. The ball has less total energy at Y than at W.
B. The ball has more kinetic energy at X than at Z.
C. The ball has more potential energy at Z than at X.
D. The ball has the same amount of total energy at W as at X.
____
3. A bowling ball and the ten bowling pins on a flat bowling alley make up a system. Based on the Law of
Conservation of Energy, which of the following statements is true?
A. Kinetic energy is increased when the bowling ball hits the pins.
B. The bowling ball always has more energy than the bowling pins.
C. The pins have more potential energy than the rolling bowling ball.
D. The total energy of the system is the same before and after the bowling ball hits the pins.
____
4. Anne and Juan rolled four different objects down a ramp. They measured the distance each object rolled and
the time until each object came to a stop. They plotted each point and connected it with a line from origin of
the graph.
Which object had the greatest average speed?
A. object A
B. object B
C. object C
D. object D
____
5. Objects moving at a constant speed have some characteristics in common. What must be true of any object
that is moving at a constant speed?
A. The object must start from rest.
B. The object cannot change direction.
C. The object must travel the same distance in a given amount of time.
D. The object must show no change in distance during a given time period.
____
6. Gabrielle did an experiment where she placed a golf ball on a ramp and calculated its speed as it rolled down
the ramp. She plotted her results on the graph below.
What was the speed of the golfball as it rolled down the ramp?
A. about 1 ft/s
B. about 2 ft/s
C. about 3 ft/s
D. about 6 ft/s
____
7. Forces act on objects that are either in direct contact or at a distance. Which forces act to keep a book on a
table?
A.
B.
C.
D.
____
mass and magnetic forces
friction and magnetic forces
gravitational and applied forces
velocity and static electric forces
8. A hydrogen atom has one proton in its nucleus, and a single electron. The diagram below shows a hydrogen
atom.
What type of force keeps the electron in orbit around the nucleus of the atom?
A. friction
B. gravity
C. electrical force
D. magnetic force
____
9. All objects exert a force on the objects around them. Joe places two beakers of water with identical masses
100 cm apart on a table. What happens to the force that each beaker exerts on the other if he adds more water
to one of the beakers?
A. Beakers of water cannot exert force on each other.
B. The amount of force exerted by the two beakers increases.
C. The amount of force exerted by the two beakers decreases.
D. The amount of force exerted by the two beakers remains the same.
____ 10. The objects shown in the following diagrams have different masses and are different distances apart. Which
diagram shows the two objects that have the greatest force of gravity acting between them?
A.
B.
C.
D.
____ 11. Devonte places a pencil and an eraser 2 cm apart on the table. He knows that both objects exert gravitational
force on each other, but observes that the two objects remain motionless. Which of the following statements is
the best explanation for why the pencil and eraser do not move toward each other?
A. The masses of the objects are too small to generate enough force to overcome other forces
acting on them.
B. The distance between the objects is too small to generate enough force to overcome other
forces acting on them.
C. The sum of the masses of the objects is too small to generate enough force to overcome
other forces acting on them.
D. The difference in the masses of the objects is too small to generate enough force to
overcome other forces acting on them.
____ 12. Amanda is studying the relationship between a planet’s mass and the weight of an object on the surface of that
planet. Her teacher writes the table below on the board to show how a planet’s gravitational force affects the
weight of a 180 kg man.
Planet
Earth
Venus
Relationship between Mass and Weight
Mass of Man (kg)
Weight of Man (N)
180
1,764
180
1,552
Based on the table, which statement best explains why the man weighs less on Venus?
A. Venus has a greater mass than Earth.
B. Earth has a greater mass than Venus.
C. The mass of the man is greater on Earth than Venus.
D. The mass of the man is greater on Venus than Earth.
____ 13. Imagine a weightless box floating in space. The following picture shows the forces acting on this box.
In what direction will this box accelerate?
A.
B.
C.
D.
____ 14. Marcos is studying the effects of force on human motion. He notices that when he exerts a force on the
ground with his foot, he moves forward. Which statement best describes why Marcos moves forward?
A. His foot exerts a greater force on the ground than the ground exerts on his foot.
B. His foot exerts a force on the ground, but the ground does not exert a force on his foot.
C. His foot and the ground exert equal forces on each other, but the force exerted by the
ground has a greater effect.
D. His foot and the ground exert equal forces on each other, and the force exerted by the foot
cancels the effect of the force exerted by the ground.
____ 15. In the picture below, the masses of the three cars are equal, but the cars each have an additional mass added to
on top.
How will the added mass affect the ability of a push to overcome the cars’ inertia and move them forward?
A. All three cars will need the same amount of force to overcome their inertia.
B. Changing the mass of the cars makes their inertia too great to overcome with a force.
C. As the mass of the car increases, the amount of force needed to accelerate the car
increases.
D. As the mass of the car increases, the amount of force needed to accelerate the car
decreases.
Grade 6 Physical Posttest
Answer Section
MULTIPLE CHOICE
1. ANS: C
A is incorrect because a bicyclist coasting down hill is a conversion of gravitational potential energy into
kinetic energy.
B is incorrect because a car engine moving a car is a conversion of chemical potential energy into kinetic
energy.
C is correct because the kinetic energy of the car is converted into gravitational potential energy as the height
of the car increases.
D is incorrect because a thrown ball after the top part of it motion is a conversion of gravitational potential
energy into kinetic energy.
STA: SC.6.P.11.1
2. ANS: D
A is incorrect because the Law of Conservation of Energy says the total energy in a system does not change
with the ball’s position.
B is incorrect because the ball has more potential energy at X than Z, and the Law of Conservation of Energy
is about the total energy.
C is incorrect because the ball has more potential energy at X than Z, and the Law of Conservation of Energy
is about the total energy.
D is correct because the Law of Conservation of Energy says that the total energy in a system is constant.
STA: SC.6.P.11.1
3. ANS: D
B is incorrect because the bowling ball will not necessarily have more energy than the pins.
D is correct because the total amount of energy in the system remains constant according to the Law of
Conservation of Energy.
C is incorrect because they are both on the ground, with no potential energy.
A is incorrect because kinetic energy is transferred from the ball to the pins.
STA: SC.6.P.11.1
4. ANS: A
A is correct because the line for object A is the steepest, so object A had the greatest average speed.
B is incorrect because while object B traveled the greatest distance, the line for object B is not the steepest.
C is incorrect because while object C traveled for the longest time, the line for object C is not the steepest.
D is incorrect because the line for object D has the least greatest slope, so object D had the lowest average
speed.
STA: SC.6.P.12.1
5. ANS: C
A is incorrect because an object at rest must accelerate to get in motion.
B is incorrect because the object can maintain its speed while changing its direction.
C is correct because the distance covered divided by a given time must be constant.
D is incorrect because this object would be at rest.
STA: SC.6.P.12.1
6. ANS: A
A is correct because a point is plotted at about 1 foot at 1 second.
B is incorrect because the ball takes 2 seconds to travel about 2 feet.
C is incorrect because the ball takes 3 seconds to travel about 3 feet.
D is incorrect because the ball takes over 5 seconds to travel 6 feet.
STA: SC.6.P.12.1
7. ANS: C
A is incorrect because mass is not a force, and a magnetic force is not acting on the book.
B is incorrect because a magnetic force is not acting on the book.
C is correct because gravitational force pushes the book down, and the applied force from the table pushes the
book up.
D is incorrect because velocity is not a force, and static electricity (electricity produced by friction) is not
acting on the book.
STA: SC.6.P.13.1
8. ANS: C
A is incorrect because friction is a contact force between two surfaces.
B is incorrect because the two particles involved each have electrical charges. Because the charges are
opposite in nature, the two particles attract each other.
C is correct because the proton carries a positive charge, which exerts an electrical force on the negatively
charged electron.
D is incorrect because magnetic force is the force that moving charges exert on each other. In the hydrogen
atom, the proton is stationary.
STA: SC.6.P.13.1
9. ANS: B
A is incorrect because all objects exert force on the objects around them.
B is correct because as the mass of one or both objects increases, the amount of force exerted increases.
C is incorrect because as the mass of one or both objects increases, the amount of force exerted increases.
D is incorrect because the amount of force exerted by an object is proportional to its mass.
STA: SC.6.P.13.1
10. ANS: C
• A is incorrect because these objects are close together but have less mass than the objects in choice C.
• B is incorrect because these objects are farther apart and have less mass than the objects in choice C.
• C is correct because gravity increases with increasing mass and decreasing distance.
• D is incorrect because these objects have the same mass as the objects in choice C but are farther apart.
STA: SC.6.P.13.2
11. ANS: A
A is correct because the masses of the two objects cannot generate the gravitational force needed to overcome
friction or other forces acting on the pencil and eraser.
B is incorrect because the closer two objects are to each other, the greater the gravitational force they exert on
each other.
C is incorrect because gravitational force is a function of the product of the masses of the two objects, not the
sum of the two masses.
D is incorrect because gravitational force is a function of the product of the masses of the two objects, not the
difference between the two masses.
STA: SC.6.P.13.2
12. ANS: B
A is incorrect because Earth has a greater mass, and thus a greater gravitational force, than Venus.
B is correct because the weight of an object increases as the mass of the planet increases The greater the
planet’s mass, the greater its gravitational force.
C is incorrect because the mass of an object does not change when its location changes.
D is incorrect because the mass of an object does not change when its location changes.
STA: SC.6.P.13.2
13. ANS: C
A is incorrect because there are unbalanced forces in the horizontal direction as well as in the vertical
direction.
B is incorrect because there are unbalanced forces in the vertical direction as well as in the horizontal
direction.
C is correct because the forces are unbalanced, and the greater forces are directed upward and to the right.
D is incorrect because the unbalanced horizontal forces are directed toward the right, not the left.
STA: SC.6.P.13.3
14. ANS: C
A is incorrect because the forces exerted by the foot and the ground are equal in magnitude but opposite in
direction.
B is incorrect because the ground exerts an equal but opposite force to the force exerted by the foot.
C is correct because equal but opposite forces can have unequal effects when objects of different masses are
involved. The mass of Earth is much greater than Marco’s mass, so the net effect of the two forces is to cause
Marcos’ much smaller mass to move in the direction of the net force.
D is incorrect because even though these two forces are equal and opposite in direction, the net force on
Marcos is in the forward direction.
STA: SC.6.P.13.3
15. ANS: C
A is incorrect because the amount of force needed to accelerate an object is directly proportional to the
object’s mass.
B is incorrect because the amount of force needed to accelerate an object is proportional to the object’s mass.
If a force is great enough, it will cause even the heaviest object to change speed or direction.
C is correct because the greater the mass of an object, the greater the force needed to change its speed and
motion.
D is incorrect because the amount of force needed to accelerate an object is directly proportional to the
object’s mass, so force increases as mass increases.
STA: SC.6.P.13.3