Chapter 12—Mechanics: Physics in Motion
Physics:

_________________________ deals with subjects studied by physicists from the time of Galileo
until about 1900: mechanics, thermodynamics, sound, light, and electricity and magnetism.

_________________________ deals with several new branches of physics that have been
developed since 1900: quantum mechanics, relativity, solid state physics, and particle physics.

12.1
I.
Physics is the primary foundation of _____________________(applied science).
Describing Motion
The Path to Modern Physics
a. Greek philosophy
i. Aristotle:
ii. Aristotle and other Greek philosophers rarely checked their ideas by
experiments; therefore, they reached many false conclusions which they
incorporated into their philosophy of nature.
b. Galileo
i. Galileo Galilei:
ii. He viewed the universe, the world, and living things as the _________________
_______________________.
c. Newton
i. Sir Isaac Newton:
ii. He discovered the _________________________ and _____________________
which became the foundation for much of modern physical science.
d. Modern physics
i. Michael Faraday and James Maxwell—laws of electromagnetism and the
harnessing of electricity in daily life
ii. Albert Einstein—theory of relativity
iii. Max Planck, Louis de Broglie, and Enrico Fermi—secrets of the atom
II.
Mechanics: The Science of Motion
a. Mechanics:
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Chapter 12—Mechanics: Physics in Motion
b. All motion is relative to some reference point.
c. Three terms are especially helpful in describing motion: speed, velocity, and
acceleration.
III.
Speed: Rate of Motion
a. Speed:
b.
c. We rarely travel at a perfectly constant speed; we travel at an ____________________.
d. The speed of a moving object at any given instant is called its _____________________.
IV.
Velocity: Speed and Direction
a. Velocity:
b. Vectors and velocity
i. Vector quantity:
ii. Physical quantities such as speed that have magnitude (amount) but no
direction are known as _____________________.
iii. Vector:
c. Combining velocities
i. Resultant:
ii. Pythagorean theorem:
iii. Vector addition:
V.
Acceleration: A Change in Motion
a. Forces and motion
i. Force:
ii. Without force, there can be no change in motion.
b. Acceleration
i. Acceleration:
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Chapter 12—Mechanics: Physics in Motion
ii. Acceleration occurs when a moving object experiences a ___________________
__________________________________.
iii.
c. Measuring acceleration
i.
ii. Speeded up—positive acceleration
iii. Slow down—negative acceleration or deceleration
12.2
I.
Motion and Forces
Newton’s Laws of Motion
a. Newton’s presented his finding to the world in his book _________________________.
b. Three Laws
i. First law (law of inertia)
1.
2. Inertia:
3. Mass:
ii. Second law
1.
2. Acceleration is _____________________ to the strength of the force
and ___________________ to the mass of the object
3.
4. Newton:
iii. Third law
1.
2.
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Chapter 12—Mechanics: Physics in Motion
II.
Momentum: “Quantity of Motion”
a. 𝑚𝑜𝑚𝑒𝑛𝑡𝑢𝑚(_____) = 𝑚𝑎𝑠𝑠 × 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦
b. The momentum of one object can be transferred to another object.
c.
d. It can be freely transferred, but it does not “disappear.”
e. Law of Conservation of Momentum
i.
III.
The Force of Gravity
a. Gravity and acceleration
i. The acceleration of the earth’s gravity does not depend on an object’s mass.
ii. All objects near the earth’s surface accelerate at the same rate when they fall,
regardless of their mass.
iii. Falling objects accelerate at a constant rate of ___________________________
iv. The mathematical relationship between distance and the acceleration of gravity
𝟏
is expressed by the equation 𝒅 = 𝒈𝒕𝟐
𝟐
b. The law of gravity
i.
ii. Gravitational attraction is greater when objects are closer together and less
when they are farther apart.
iii.
iv. Capital G is a fixed number called the __________________________________
(6.673 × 10−11 𝑁 ∙ 𝑚2 /𝑘𝑔2).
IV.
Other Forces of Nature
a. Gravity
b.
i. Strongest of the fundamental forces
ii. Acts only within atomic nuclei
iii. Acts to bind protons and neutrons together into an atomic nucleus
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Chapter 12—Mechanics: Physics in Motion
c.
i. Affects only those particles that have an electric charge
ii. Can either attract or repel
iii. Manifests in two ways
1.
a. Force exerted on electrically charged objects by stationary
charge particles
b. Responsible for static electricity
2.
a. Charged particles are in motion (whether moving or spinning)
b. Responsible for all forms of magnetic attraction
iv. Involved in the propagation of electromagnetic waves, which compose light and
other forms of radiation
d.
i. Affects all elementary particles
ii. The only force that significantly affects the neutrino
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