Welcome 1 Of 2 Introduction To Physics 101
Welcome 1 Of 2introductionwelcome To Physics 1010 Physics Is The St
Welcome to Physics 1010! Physics is the study of physical phenomena in nature. The concepts of physics such as force, motion, matter, and energy are involved in every activity. Physics can help you understand common occurrences of daily life, such as a rainbow, a spherical drop of water, lightning, and your reflection in a mirror. This course aims at conveying some of the concepts of physics to help you understand the common physical phenomena.
A core concept this course will highlight is that nature obeys some fundamental laws. It’s amazing how so many seemingly unrelated phenomena obey a common set of laws. One of the quests of physics is unification—to be able to explain diverse phenomena with the same set of laws. Physics and math go hand in hand, and for this course, you will use algebra (learned in MTH1010 College Math) as a tool to solve quantitative problems. The lectures cover key concepts, and they are supplemented by reading assignments, practice exercises, and experiments.
Online discussions give you the opportunity to exchange your views and learning with your classmates. Physics is a vast subject and six weeks is a short time to study it. You will need to do a lot of reading from the lectures, textbooks, and Web sites. You should plan to spend about three hours a day for this course.
Weekly Overview
Physics also deals with physical quantities such as length, time, mass, speed, velocity, and their interrelationships. This week's lectures will discuss the units and standards of physical quantities, specifically how they are measured. You will also learn to convert units from the imperial and US customary units to the metric system and vice versa. This week will also cover the classification of physical quantities as vectors or scalars and the differences between vectors and scalars. Because of these differences, the method to add vectors is different from the method used to add scalars. You will learn how to add vectors and find their components along the direction of any coordinate axis.
Finally, you will learn about kinematics—the study of the relationship between the position, velocity, and acceleration of an object. You will analyze motion along a straight line and a curved path and calculate the velocity and distance traveled when acceleration is constant. In addition, you'll explore how gravity affects objects that fall freely or objects that are thrown vertically upwards. Ready to start? Let's go!
Physical Quantities Units and Standards
Imagine a customer going to a grocery store and asking for five sugar or one milk! The clerk will be confused because the customer hasn't specified the units. A quantity is always specified with a unit such as pound or gallon. In the above situation, the customer could have asked for five pounds of sugar and a gallon of milk. Note that units tell us two important pieces of information about a measurement.
They tell us what type of measurement is involved, as well as its scale. For example, if given a measurement of three meters, the “meters” indicates that we are dealing with a length. It also informs us of the scale. For instance, three inches is also a length, but it is a different scale than three meters. Before specifying or using a unit, it needs to be defined; before measuring length in feet, you must know how much one foot is.
Once defined, a unit becomes a standard for all subsequent measurements. A standard should be precise, invariable, and accessible. A widely used system of units is the international system of units, also called the SI system or metric system, which comprises seven base quantities (see SI Base Quantities table). Each quantity has a unit for which a primary standard is carefully defined.
The Standard for Mass
The mass of a substance is the quantity of matter it contains. The standard mass of one kilogram is by common agreement the mass of a cylinder made of platinum-iridium maintained by the International Bureau of Weights and Measures near Paris.
The Standard for Time
The second is defined as the period in which there are a certain number (specifically, 9,192,631,770) of vibrations of a particular radiation emitted by a Cesium-133 atom.
The Standard for Length
The meter is defined as the distance that light travels in a vacuum in 1/299,792,458 of a second. Because the speed of light in a vacuum is constant and can be calculated accurately as 299,792,458 meters per second, this value was fixed as the speed of light.
Measurement and Its Importance
Once units are defined, we can use them to measure quantities. Measurements are important to us in many ways. Even in daily life, we frequently measure quantities. Examples include measuring body temperature, checking blood pressure, monitoring tire pressure, tracking body weight, purchasing goods based on weight or volume, and measuring distance or velocity of a vehicle.
Measurement is central to physics because any new scientific theory proposed must be tested through experiments, which require precise measurements.
Conversion of Units
Often, there is a need to convert quantities from one unit to another. For example, converting miles to kilometers, or pounds to kilograms, to ensure consistency or align with international standards.
Scalars and Vectors
Quantities can be classified as scalars or vectors. Scalar quantities are described solely by magnitude; for example, mass (4 kg), area, temperature, and volume. Vector quantities require both magnitude and direction; for example, displacement (3 m northeast), force, velocity, and acceleration. Recognizing whether a quantity is a scalar or a vector helps in understanding and solving physics problems.
Addition of Vectors
Adding scalar quantities involves straightforward arithmetic addition of their magnitudes. However, adding vectors involves considering both magnitude and direction, often using the triangle rule of vector addition. Components of vectors along coordinate axes can be determined to analyze effect in specific directions, which is especially useful when resolving forces or calculating projectile motions.
Components of a Vector
Vectors can be broken into components along x and y axes. The component of a vector along an axis is determined by the magnitude of the vector and the angle it makes with the axis, using trigonometric functions. Components are essential in resolving vectors into perpendicular directions to analyze motion or force effects precisely.
Kinematics: The Study of Motion
Kinematics describes the motion of objects without considering the forces causing it. Key quantities include displacement, velocity, and acceleration. Displacement is a vector indicating change in position; velocity is the rate of change of displacement; and acceleration is the rate of change of velocity.
Displacement takes into account the initial and final positions, regardless of the path taken. Velocity points in the direction of motion; speed, a scalar, measures the magnitude of velocity, ignoring direction.
Acceleration and Its Units
Acceleration indicates how quickly an object's velocity changes, measured in meters per second squared (m/s²). An object moving with constant velocity has zero acceleration; if velocity increases or decreases, acceleration is present.
Types of Motion
Motion can be linear or curved. Examples include free-fall, vertical throws, and uniform motion on a straight road. Uniform acceleration involves constant change in velocity, allowing the use of kinematic equations such as vf = vi + at and d = vit + (1/2) at² to analyze motion.
Vertical Motion and Gravity
Vertical motion under gravity involves constant acceleration 'g' equal to 9.8 m/s² downward. Equations of motion account for initial velocities, time, and gravitational acceleration, explaining phenomena like free fall and upward projectile motion.
Curved Path Motion and Centripetal Acceleration
Objects moving along curved paths, such as a roller coaster, experience acceleration due to changing velocity direction, even if speed remains constant. The acceleration points toward the center of the curvature and is called centripetal acceleration, calculated as ac = v² / r, where r is the radius of the curve.
Summary
This week’s content covered fundamental concepts of units and measurement, the distinction between scalars and vectors, the process of combining vectors, and an introduction to kinematics, focusing on displacement, velocity, and acceleration. Understanding these core principles is essential for analyzing motion and predicting physical phenomena in various contexts.
References
- Halliday, D., Resnick, R., & Walker, J. (2014). Fundamentals of Physics. 10th Edition. Wiley.
- Serway, R. A., & Jewett, J. W. (2018). Physics for Scientists and Engineers with Modern Physics. 10th Edition. Cengage Learning.
- Tipler, P. A., & Mosca, G. (2008). Physics for Scientists and Engineers. 6th Edition. W. H. Freeman.
- Giancoli, D. C. (2013). Physics: Principles with Applications. 7th Edition. Pearson.
- Knight, R. D. (2013). Physics for Scientists and Engineers: A Strategic Approach with Modern Physics. 3rd Edition. Pearson.
- Moore, C. (2014). Measurement in Physics. Physics Education, 49(4), 439–448.
- International Bureau of Weights and Measures. (2019). SI Brochure: The International System of Units (SI). BIPM.
- Young, H. D., & Freedman, R. A. (2019). University Physics with Modern Physics. 15th Edition. Pearson.
- Knight, R. D. (2012). Physics for Scientists and Engineers: A Strategic Approach with Modern Physics. Pearson.
- Harrison, J. (2010). The Importance of Measurement in Physics. Journal of Physics Education, 45(2), 85–90.