sample test for grade 8 science

1. DRILLS
FOR
GRADE 8
SCIENCE

2. Describe the
difference between
a question,
generated through
observation, and a
hypothesis.
a. They are the same.
b. A hypothesis has been thoroughly
tested and found to be true.
c. A hypothesis is a tentative assumption
based on what is already known.
d. A hypothesis is a broad explanation
firmly supported by evidence.

3. What is a
scientific
model and
how is it
useful?
a. A scientific model is a representation of
something that can be easily studied directly. It is
useful for studying things that can be easily
analyzed by humans.
b. A scientific model is a representation of
something that is often too difficult to study directly.
It is useful for studying a complex system or
systems that humans cannot observe directly.
c. A scientific model is a representation of scientific
equipment. It is useful for studying working
principles of scientific equipment.
d. A scientific model is a representation of a
laboratory where experiments are performed. It is
useful for studying requirements needed inside the
laboratory.

4. Which of
the
following
statements
is correct
about the
hypothesis
?
a. The hypothesis must be
validated by scientific experiments.
b. The hypothesis must not include
any physical quantity.
c. The hypothesis must be a short
and concise statement.
d. The hypothesis must apply to all
the situations in the universe.

5. What is a
scientific
theory?
a. A scientific theory is an explanation
of natural phenomena that is
supported by evidence.
b. A scientific theory is an explanation
of natural phenomena without the
support of evidence.
c. A scientific theory is an educated
guess about the natural phenomena
occurring in nature.
d. A scientific theory is an uneducated
guess about natural phenomena
occurring in nature.

6. Compare
and contrast
a hypothesis
and a
scientific
theory.
a. A hypothesis is an explanation of the natural world
with experimental support, while a scientific theory is an
educated guess about a natural phenomenon.
b. A hypothesis is an educated guess about natural
phenomenon, while a scientific theory is an explanation
of natural world with experimental support.
c. A hypothesis is experimental evidence of a natural
phenomenon, while a scientific theory is an explanation
of the natural world with experimental support.
d. A hypothesis is an explanation of the natural world
with experimental support, while a scientific theory is
experimental evidence of a natural phenomenon.

7. The speed limit on
some interstate
highways is
roughly 100 km/h.
How many miles
per hour is this if
1.0 mile is about
1.609 km?
a. 0.1 mi/h
b. 27.8 mi/h
c. 62 mi/h
d. 160 mi/h

8. You notice that it
takes more force to
get a large box to
start sliding across
the floor than it takes
to get the box sliding
faster once it is
already moving.
Create a testable
hypothesis that
attempts to explain
this observation.
a. The floor has greater distortions of
space-time for moving the sliding box faster
than for the box at rest.
b. The floor has greater distortions of
space-time for the box at rest than for the
sliding box.
c. The resistance between the floor and the
box is less when the box is sliding then
when the box is at rest.
d. The floor dislikes having objects move
across it and therefore holds the box rigidly
in place until it cannot resist the force

9. The speed of
sound is measured
at 342 m/s on a
certain day. What
is this in km/h ?
Report your
answer in scientific
notation.

10. The speed of sound is measured
at 342 m/s on a certain day. What
is this in km/h ? Report your
answer in scientific notation.

11. The speed of sound is measured
at 342 m/s on a certain day. What
is this in km/h ? Report your
answer in scientific notation.

12. Rob drove to the
nearest hospital with
an average speed of
v m/s in t seconds.
In terms of t, if he
drives home on the
same path, but with
an average speed of
3v m/s, how long is
the return trip home?
a. t/6
b. t/3
c. 3t
d. 6t

13. Rob drove to the nearest hospital
with an average speed of v m/s in t
seconds. In terms of t, if he drives
home on the same path, but with
an average speed of 3v m/s, how
long is the return trip home?
a. t/6
b. t/3
c. 3t
d. 6t

14. What can
you infer
from the
statement,
Velocity of
an object is
zero?
Object is in linear motion with
constant velocity.
a.
Object is moving at a constant
speed.
b.
Object is either at rest or it returns
to the initial point.
c.
Object is moving in a straight line
without changing its direction.
d.

15. An object has an
average speed
of 7.4 km/h.
Which of the
following
describes two
ways you could
increase the
average speed
of the object to
14.8 km/h?
a. Reduce the distance that the object travels
by half, keeping the time constant, or keep the
distance constant and double the time.
b. Double the distance that the object travels,
keeping the time constant, or keep the distance
constant and reduce the time by half.
c. Reduce the distance that the object travels to
one fourth, keeping the time constant, or keep
the distance constant and increase the time by
fourfold.
d. Increase the distance by fourfold, keeping
the time constant, or keep the distance
constant and reduce the time by one-fourth.

16. What is the
rate of change
of velocity
called?

17. A ball rolls along the
ground, moving from north
to south. What direction is
the frictional force that acts
on the ball?

18. What does it
mean for two
quantities to
be inversely
proportional
to each
other?
a. When one variable increases,
the other variable decreases by a
greater amount.
b. When one variable increases,
the other variable also increases.
c. When one variable increases,
the other variable decreases by
the same factor.
d. When one variable increases,
the other variable also increases
by the same factor.

19. Only two forces
are acting on an
object: force A to
the left and force
B to the right. If
force B is greater
than force A, in
which direction
will the object
move?
a. To the right
b. To the left
c. Upward
d. The object does not move

20. A person pushes an
object of mass 5.0
kg along the floor by
applying a force. If
the object
experiences a
friction force of 10 N
and accelerates at
18 m/s2, what is the
magnitude of the
force exerted by the
person?
a. −90 N
b. −80 N
c. 90 N
d. 100 N

21. What kind of
force is
friction?
a. External force
b. Internal force
c. Net force
d. None of these

22. Which of
these
quantities is
constant in
uniform
circular
motion?
a. Speed
b. Velocity
c. Acceleration
d. Displacement

23. Which of these quantities impact centripetal
force?

24. Which of these quantities impact centripetal
force?

25. Which expression
represents
power?

26. Why is this
expression
for kinetic
energy
incorrect?
a. The constant is missing.
b. The term should not be
squared.
c. The expression should be
divided by 2 .
d. The energy lost to friction
has not been subtracted.

27. A boy pushes his
little sister on a sled.
The sled accelerates
from 0 to 3.2 m/s . If
the combined mass
of his sister and the
sled is 40.0 kg and
18 W of power were
generated, how long
did the boy push the
sled?
a. 205 s
b. 128 s
c. 23 s
d. 11 s

28. A runner at the start
of a race generates
250 W of power as
he accelerates to 5
m/s.
If the runner has a
mass of 60 kg, how
long did it take him
to reach that
speed?
a. 0.33 s
b. 0.83 s
c. 1.2 s
d. 3.0 s

29. What are the
SI units for
electric
current?

30. The equivalent
unit for an ohm
is a ________.

31. How many
10-Ω resistors
must be
connected in
series to
make an
equivalent
resistance of
80 Ω?
a. 80
b. 8
c. 20
d. 40

32. Give a
verbal
expression
for Ohm’s
law.
A. Ohm’s law says that the current through a
resistor equals the voltage across the resistor
multiplied by the resistance of the resistor.
b. Ohm’s law says that the voltage across a
resistor equals the current through the resistor
multiplied by the resistance of the resistor.
c. Ohm’s law says that the resistance of the
resistor equals the current through the resistor
multiplied by the voltage across a resistor.
d. Ohm’s law says that the voltage across a
resistor equals the square of the current
through the resistor multiplied by the resistance
of the resistor.

33. Ohm’s Law

38. Electric Power