Focus On Physical Science: California Grade 8

Unit 1: Motion and Forces

Unit Tests

1.
What is the mass of an ice cube with a density of 0.92 g/cm3 and a volume of 5 cm3? 8.b
A)4.6 g
B)5.4 g
C)0.18 g
D)4.08 g
2.
What is the density of an object whose mass is 15.0 g and whose volume is 5.0 cm3? 8.b
A)3.0 km/m3
B)3.0 g/cm3
C)0.33 g/cm3
D)75.0 g/cm3
3.
What is your speed if you traveled a distance of 5 km in 0.25 hours? 1.c
A)1.25 km/h
B)5 km/h
C)20 km/h
D)0.05 km/h
4.
How long does it take a car traveling with an average speed of 60 km/h to travel 390 km? 1.c
A)0.65 h
B)0.15 h
C)2.34 h
D)6.5 h
5.
How long will it take a runner to run a 400 m race if the runner's average speed is 8 m/s? 1.c
A)3,200 s
B)5 h
C)20 s
D)50 s
6.
If the forces acting on an object are 37 N to the right and 19 N to the left, what is the net force on the object? 2.b
A)56 N to the right
B)18 N to the left
C)18 N to the right
D)56 N to the left
7.
What are the two forces acting a book at rest on a table? 2.d
A)a normal force and static friction
B)gravity and static friction
C)gravity and a normal force
D)gravity and sliding friction
8.
What is Newton's second law of motion? 2.f
A)mass equals acceleration divided by net force
B)acceleration equals net force divided by mass
C)acceleration equals normal force divided by inertia
D)net force equals mass divided by acceleration
9.
How is the density of an object calculated? 8.b
A)Multiply the object's mass by its volume.
B)Divide the volume of an object by its mass.
C)Add the mass of the object and its volume.
D)Divide the mass of the object by its volume.
10.
For which situation is the velocity constant? 1.e
A)An object moves in a straight line with constant speed.
B)An object turns at a constant speed.
C)An object moving in a straight line speeds up.
D)An object moves in a circular path.
11.
Which does not define a reference direction relative to a reference point? 1.a
A)in front of
B)+5 cm
C)away from
D)left
12.
A net force that causes an object to move in a circular path is called _______. 2.e
A)elastic force
B)frictional force
C)centripetal force
D)normal force
13.
Which of these is a contact force? 2.c
A)magnetic force
B)gravitational force
C)electric force
D)frictional force
14.
The normal force is what type of force? 2.d
A)frictional force
B)tension force
C)compression force
D)gravitational force
15.
Which is not a unit for density? 8.a
A)kg/m3
B)km/m3
C)g/cm3
D)g/mL
16.
When an object is speeding up, the acceleration vector is _______. 1.e
A)is in the direction opposite to the velocity vector
B)in the same direction as the velocity vector
C)is perpendicular to the velocity vector
D)can be in any direction
17.
How is an object moving if the line plotted on a position-time graph is a straight line sloping upward? 1.f
A)It is slowing down.
B)It is speeding up.
C)It is moving with constant speed
D)It is accelerating.
18.
How is an object moving if the line plotted on a speed-time graph curves upward? 1.f
A)It is at rest.
B)It is slowing down.
C)Its speed is constant.
D)It is speeding up.
19.
Density is a physical property because it can be measured without changing the _______ of a material. 8.a
A)weight
B)volume
C)mass
D)composition
20.
Which two things does the acceleration of an object depend on? 2.f
A)mass and inertia
B)inertia and velocity
C)mass and net force
D)net force and velocity
21.
What is the unit for force? 2.b
A)newton
B)meter/second
C)meter/second2
D)kilogram meter
22.
If an object is slowing down, the net force on the object is in which direction? 2.e
A)the opposite direction to the velocity
B)the same direction as the velocity
C)perpendicular to the velocity
D)perpendicular to the gravitational force
23.
The length of an arrow representing a velocity vector depends on the object's ______. 1.d
A)acceleration
B)speed
C)position
D)direction
24.
Which is not needed to describe an object's position? 1.a
A)reference direction
B)reference point
C)velocity
D)distance from reference point
25.
The length of arrow representing a force vector depends on the ______. 2.a
A)velocity of the object
B)direction of the force
C)speed of the object
D)strength of the force
26.
The formula V = lwh is used to calculate the volume of what type of object? 8.b
A)sphere
B)irregular solid
C)rectangular solid
D)cylinder
27.
How does the density of 25.0 g of a substance compare with the density of 5.0 g of the same substance? 8.a
A)The density of 25-g sample is 5 times larger.
B)The densities are the same.
C)The density of 25-g sample is 5 times larger.
D)The density of 25-g sample is 5 times smaller.
28.
Which is true if the net force on an object is not zero? 2.c
A)The net force is a normal force.
B)The forces on the object are balanced.
C)The net force is a centripetal force.
D)The forces on the object are unbalanced.
29.
What will happen if the density of an object placed in a fluid is greater than the density of the fluid? 8.d
A)The object will rise upward in the fluid.
B)The object will float on top of the fluid.
C)The object will sink downward in the fluid.
D)The object will float below the surface of the fluid.
30.
What must be true for an object to float? 8.c
A)The object's weight is greater than the buoyant force.
B)The buoyant force equals the object's weight.
C)The object's volume equals the volume of fluid displaced.
D)The mass of the object equals the buoyant force.
31.
What causes the upward buoyant force on an object placed in a fluid? 8.c
A)The pressure exerted by the fluid increases with depth in the fluid.
B)The pressure exerted by the fluid is the same at all depths.
C)The pressure exerted by the fluid is always upward.
D)The pressure exerted by the fluid on all sides of the object is balanced.
32.
What is Archimedes' principle? 8.c
A)The buoyant force on an object equals the volume of the fluid the object displaces.
B)The buoyant force on an object equals the weight of the fluid the object displaces.
C)The pressure on an object equals the weight of the fluid the object displaces.
D)The pressure on an object equals the density of the fluid.
33.
What is an object's acceleration? 1.e
A)The rate of change of position with time.
B)The rate of change of distance with time.
C)The rate of change of velocity with time.
D)The rate of change of displacement with time.
34.
What is the weight of an object? 2.d
A)the size of the object
B)the mass of the object
C)the gravitational force on the object
D)the elastic force on the object
35.
To specify an object's velocity, ______ must be given. 1.d
A)the acceleration and direction of motion
B)the acceleration and speed
C)the speed
D)the speed and direction of motion
36.
A hydrometer sinks twice as deep in a certain fluid as it does in water. This means that _______. 8.d
A)the volume of the fluid is twice the volume of water.
B)the density of the fluid is twice the density of water.
C)the volume of the fluid is one half the volume of water.
D)the density of the fluid is one half the density of water
37.
According to Archimedes' principle, an object floats if _______. 8.c
A)The weight of the object equals the volume of the fluid displaced.
B)The weight of the object equals the weight of the fluid displaced.
C)The volume of the object equals the volume of the fluid displaced.
D)The mass of the object equals the weight of the fluid displaced.
38.
A balloon rises in air because _______. 8.d
A)the density of the balloon is less than the density of air
B)the density of the balloon equals the density of air
C)the weight of the balloon is greater than the weight of the air the balloon displaces
D)the weight of the balloon equals the buoyant force on the balloon
39.
The combination of all the forces acting on an object is called the __________. 2.b
A)balanced force
B)net force
C)unbalanced force
D)centripetal force
40.
A speedometer measures a car's _______. 1.b
A)velocity
B)average speed
C)instantaneous speed
D)acceleration
41.
What is equal to the total distance traveled divided by the total time elapsed? 1.b
A)acceleration
B)instantaneous speed
C)velocity
D)average speed
42.
The slope of a line on a speed-time graph is equal to the _______ of an object. 1.f
A)position
B)acceleration
C)velocity
D)speed
43.
According to the law of universal gravitation, the gravitational force between two objects depends on ________. 2.g
A)velocity of the objects
B)the elastic forces on the objects and the distance between them
C)the masses of the objects and the distance between them
D)the inertia and velocity of the objects
44.
The depth to which a hydrometer sinks in fluid depends on the _______. 8.d
A)mass of the fluid
B)density of the fluid
C)volume of the fluid
D)weight of the fluid
45.
If a car is moving with a constant velocity, then the forces on the car are _______. 2.c
A)balanced
B)unbalanced
C)zero
D)normal
Grade 8
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