Physics for Life Sciences I – Lecture 1 (Sections 1.1–1.5) Study Notes

Course Overview and Logistics

Course Structure and Grading

This course introduces fundamental concepts in physics tailored for life sciences students. The grading is based on multiple components to ensure a comprehensive assessment of student understanding and participation.

• Homework: 10%

• Clicker Score: 10% (participation and correctness)

• Midterm #1: 17.5%

• Midterm #2: 17.5%

• Labs: 25%

• Final Exam: 20%

• Bonus: Up to 5% extra for pre-lecture homework

Students must independently pass both laboratory and lecture portions to pass the course. The grading scale may be adjusted to reflect overall class performance, with top 90% guaranteeing an "A", top 75% a "B", and top 60% a "C".

Textbook and Resources

• Textbook: "College Physics: A Strategic Approach" (4th Edition) by Knight, Jones, Field

• MasteringPhysics: Online homework and eText access required

• Course Platform: Brightspace (PHY121.00)

Homework is assigned via MasteringPhysics, with one homework per lecture (two per week), due approximately one week after the lecture at 9:00am. The lowest three homework scores are dropped. Bonus homework is available for extra credit.

Clickers

• In-person students: Use the Turning Point app ("PointSolutions") for clicker questions during lectures.

• Online students: Answer clicker questions on Brightspace after watching lecture videos.

• Grading: For in-person students, 50% of clicker grade is attendance, 50% correctness. For online students, 100% is correctness.

Labs

• All students must complete all labs; none are dropped.

• Receiving zero on more than three labs results in failing the lab portion.

• Final grade is an average of lecture and lab grades; failing either results in failing the course.

• University-excused absences require documentation and a make-up request.

Exams

• Two midterms and one final exam; formats announced in class and on Brightspace.

• Midterm 1: Wednesday, September 17th @ 8:15–9:35pm

• Midterm 2: Friday, November 4th @ 8:15–9:35pm

• Final Exam: Friday, December 11th @ 2:15–5:00pm

Office Hours and Help Room

• Staffed by teaching assistants and professors.

• Schedules posted on Brightspace.

• Available both in-person and via Zoom.

Fundamental Concepts in Physics (Sections 1.1–1.5)

Section 1.1: Motion – A First Look

Motion is the change in an object's position or orientation over time. The path along which an object moves is called its trajectory.

• Motion Diagram: A series of images showing an object's position at equal time intervals, useful for visualizing motion (constant speed, speeding up, slowing down).

• One-dimensional motion: Movement along a straight line.

• Two-dimensional motion: Movement with changes in both speed and direction.

Section 1.2: Models and Modeling

Physical theories are mathematical models developed to explain observed phenomena. Theories must be falsifiable—able to be tested and potentially disproven by experiments.

• Example: The evolution of the theory of gravity, from Aristotle's separate theories for terrestrial and celestial objects, to Newton's unified law, and Einstein's general relativity.

• Particle Model: Simplifies a moving object by treating all its mass as concentrated at a single point.

Section 1.3: Position and Time

To describe motion quantitatively, we assign numbers to position and time using a coordinate system.

• Coordinate System: Defined by an origin and axes with positive and negative directions.

• Position (x): The location of an object along an axis, measured from the origin.

• Time (t): Each position in a motion diagram is labeled with its corresponding time.

• Displacement ($\Delta x$): The change in position, $\Delta x = x_f - x_i$.

• Time Interval ($\Delta t$): The elapsed time between two events, $\Delta t = t_f - t_i$.

Example: If Emily moves from 3 miles east to 2 miles west of a water tower in half an hour, her displacement is $-5$ miles (westward).

Section 1.4: Velocity

Velocity describes both the speed and direction of an object's motion. Uniform motion refers to motion at constant speed in a straight line.

• Speed: How fast an object moves, regardless of direction.

• Velocity: Displacement divided by time interval; includes direction.

Formulas:

• Average Velocity: $v = \frac{\Delta x}{\Delta t}$

• Speed: $\text{Speed} = \frac{\text{Distance Traveled}}{\text{Time Interval}}$

Example: An albatross moves from 60 miles east to 80 miles east of its roost in 0.25 hours. Its velocity is $\frac{20\,\text{mi}}{0.25\,\text{h}} = 80\,\text{mi/h}$ east.

Section 1.5: Significant Figures, Scientific Notation, and Units

Measurements in physics must be reported with appropriate precision and units.

• Significant Figures: Digits in a measurement that are reliably known. The number of significant figures reflects the precision of the measurement.

• Rules:

  • For multiplication/division: The answer should have the same number of significant figures as the least precise number.

  • For addition/subtraction: The answer should have the same number of decimal places as the least precise number.

  • Exact numbers (e.g., counting numbers, defined constants) do not affect significant figures.

• Scientific Notation: Used to express very large or small numbers clearly and to indicate significant figures.

  • Example: $6370000\,\text{m} = 6.37 \times 10^6\,\text{m}$

  • Example: $0.0000075\,\text{m} = 7.5 \times 10^{-6}\,\text{m}$

• SI Units: The standard system of units in science.

  • Length: meter (m)

  • Time: second (s)

  • Mass: kilogram (kg)

• Unit Conversion: Important for translating between different systems (e.g., English and SI units).

Table: Common SI Units

Quantity	Unit	Abbreviation
Time	second	s
Length	meter	m
Mass	kilogram	kg

Table: Approximate Unit Conversions

SI Unit	Approximate English Equivalent
1 kg	2 lb
1 m	3 ft
1 cm	0.4 in
1 km	0.6 mi

Summary of Key Concepts

• Motion diagrams and the particle model help visualize and simplify the study of motion.

• Position and displacement are described using coordinates and differences in position.

• Velocity and speed quantify how fast and in what direction an object moves.

• Significant figures and scientific notation ensure clarity and precision in measurements.

• SI units are the standard for scientific measurements; unit conversion is essential for practical applications.

Additional info: These notes are based on the syllabus and introductory lecture slides for Physics for Life Sciences I, covering foundational concepts in motion, measurement, and scientific modeling.