Download Semester Exam Study Guide

Semester Exam Study GuideAnswer Review
8th Grade
1. An object is in motion if its position
changes relative to a ______ ______.
Reference Point
2. What is the basic SI unit of length?
Meter
3. When you know the speed and direction of
an object’s motion, you know its ____.
Velocity
4. What is negative accleration? Give an
example?
Slowing down- a car approaching a red light
5. A reference point is used for ______.
Determining if something is moving.
6. Look at the graph on page 324. Does the
graph show a negative acceleration?
No
7. Page 324 graph: What does the line
represent in terms of speed and
acceleration?
Speed increases; object accelerates.
8. Page 324 graph: What is the acceleration
between 0 and 6 seconds?
2m/s2
9. What units should be used when
expressing acceleration?
m/s2
10. Changing direction in one way that an
object can _________.
accelerate.
11. If an object moves in the same direction
at a constant speed for 4 hours, what can
you say about its velocity and acceleration?
It did not change
12. Newton’s first law of motion is also called
the law of _______.
Inertia
13. Between a bowling ball, beach ball,
tennis ball, and badminton birdie..which
would have more inertia?
A bowling ball.
14. The force that slows down the movement
between objects is _________.
Friction
15. Give an example of increasing friction
intentionally.
Throwing sand on an icy driveway
16. Balanced forces do not affect the
motion of an object because
They are equal and opposite in direction.
17. What does the law of conservation of
momentum state?
Momentum cannot be lost, only transferred.
 18. What is the difference between mass and
weight?
Weight- measures the gravitational pull by the earth on an
object.
 19. A 200 kg cart is being accelerated by a tractor
at a rate of 4 m/s2. How much force is the tractor
putting on the cart?
F = MA
F = 200 X 4 = 800 N
 20. Newton’s 3rd law says that for every action
force there is a reaction force that ____ and ___.
Equal and oppsite.
 21. Which of Newton’s laws relates force, mass,
and acceleration in the formula F= ma?
2nd
 22. One way to increase acceleration of an object is
by _____ ____.
Increasing Force
 23. A 0.5 kg ball is rolled across the floor with a
velocity of 2.5 m/s. What is the ball’s momentum?
Momentum = mass X velocity
Momentum = 0.5 kg X 2.5 m/s
1.25 kg X m/s
24. Why is it possible to throw a 0.15 kg
baseball much further than a 7kg bowling
ball?
The same force is applied to a lighter object.
25. A speedboat pulls a 60 kg water skier.
The force causes the skier to accelerate at
1.5 m/s2. Calculate the net force that
causes this acceleration.
F = M X A
F = 60 X 1.5
F = 90
26. How do snowshoes enable a person to
walk on deep snow?
Increases the area over which the person’s
weight is distributed.
27. What happens to air pressure as
elevation increases?
It decreases
28. Water pressure increases as ____ ___.
Depth increases
29. What scientific rule describes why water
squirts from a plastic bottle when it is
squeezed?
Pascal’s
30. Which principle explains flight?
Bernoulli’s
31. During high winds, the windows in a
building may bulge outward because the air
pressure inside the building is ___ ____
the air pressure outside the building.
Greater Than
32. What scientific rule states that the
buoyant force on an object is equal to the
weight of the fluid displaced by the object?
Archimedes
33. A pitcher is able to throw a curve ball
partly because of ____ _____.
Bernoulli’s Principle
34. Pascal’s principle states that when force
is applied to a confined fluid, the change in
pressure is transmitted _________.
Equally to all parts of the fluid
35. What 2 factors does pressure depend
on?
Force & Area
36. What must happen for work to be done
on an object?
The object must move some distance as a result
of a force.
37. Give an example of work being done.
Pushing a child on a swing
38. The mechanical advantage of a machine
is the number of times a machine increases
________.
The force exerted on the machine.
39. The mechanical advantage of a machine
that changes only the direction of force is
_____.
1
40. The ideal mechanical advantage would
equal the actual mechanical advantage if
there were no loses due to _______.
Friction
41. All machines have a(n) _____ of less
than 100%
Efficiency
42. The output work of a machine is
14,000J. If the input work is 17,500 J, the
efficiency is _____.
Efficiency = output / input X 100%
Efficiency = 14,000J / 17,500 J
80%
43. Frank does 2,800J of work in climbing a
set of stairs. If he does the work in 3
seconds, what is his power output?
Power = Work / Time
Power = 2,800 J / 3 seconds=
933.3
44. How much work does an elephant do
while moving a circus wagon 35 meters with
a pulling force of 1,500 N.
Work = Force X Distance
Work = 1,500 N X 35 Meters
52,500
45. A machine makes work easier by
multiplying force or __________, or by
changing direction.
Distance
46. The ability to do work is _____.
Energy
47. Energy associated with motion is ____
_____.
Kinetic energy
48. Kinetic energy increases as
___________.
Both mass and velocity increase.
49. Give an example of an object that has
kinetic energy?
Rolling bowling ball
50. What does the law of conservation of
energy state?
No energy is created or destroyed
51. A change from one form of energy into
another is a(n) ______ ______.
Energy Transformation
52. Potential energy that depends on height
is _____ ______ _____.
Gravitational Potential Energy
53. What would always be true of an object
possessing a kinetic energy of 0 joules?
It is at rest
54. Which would always be true of an object
possessing a potential energy of 0 joules?
It is on the ground
55. If an object is at rest, it certainly does
not possess this form of energy.
Kinetic
56. A light bulb transforms _____ energy
into ____ energy.
Electrical to light
57. A ball thrown into the air has its greatest
_____ energy as it reaches its highest
point.
Potential
58. As water runs over a waterfall, its ____
energy is transformed into ____ energy.
Potential to kinetic
59. A baseball flying through the air has
____ energy because of its motion and ____
energy because of its position.
Kinetic and potential
60. A large truck and a small car are moving
at the same speed. The truck has greater
kinetic energy because its _____ is greater.
mass
61. How can moving water be used to
produce electricity?
Because most forms of energy can be changed
into other forms.
62. The rate at which energy is transferred
is called _______.
Power
63. Waves that move the particles of a
medium parallel to direction the wave is
traveling is ______ ______.
Longitudinal waves
64. A disturbance that transfers energy from
place to place is called _____.
Wave
65. The distance between 2 corresponding
parts of a wave is the _______.
Wavelength
66. Electromagnetic waves can transfer
energy without a(n) _____.
Medium
67. Frequency is measured in ______.
hertz
68. Which EM waves have the longest
wavelengths and lowest frequencies?
Radio waves
69. Red has the longest ______ of any color
of visible light.
Wavelength
70. The EM waves with the highest
frequencies are called _____ ____.
Gamma Rays
71. The _______ of a mechanical wave is a
direct measure of its energy.
amplitude
72. The _______ the wavelength a wave
has, the ______ its frequency.
Shorter; higher
73. What is a transverse wave?
A disturbance that transfers energy perpendicular
to its medium
74. What is an example of a longitudinal
wave?
Sound
75. What is the low point on a transverse
wave?
Trough
76. If a person is generating a wave through
a medium, what is the person transferring to
that medium?
Energy