R E B O OT C O M PU T E R S E RVI C ES I N C . · C O L L E G E ST U DY S E R I ES
Physics 101
The Complete Study Guide to Introductory Mechanics
Formulas · Worked Examples · Practice Problems + Solutions
Inside this guide
1 · Units, Measurement & Vectors
2 · Motion in One & Two Dimensions
3 · Newton's Laws of Motion
4 · Work, Energy & Power
5 · Momentum & Collisions
6 · Circular Motion & Gravitation
7 · Master Formula Sheet
8 · 20 Practice Problems with Full Solutions
9 · Glossary of Key Terms
A self-study companion for first-semester physics · rebootcs.com
, 1 · Units, Measurement & Vectors
Physics is a quantitative science: every claim is tied to a measurable quantity with a number and a unit. Mastering units
and vectors early prevents the majority of errors students make later.
SI Base Units
Quantity Unit Symbol
Length meter m
Mass kilogram kg
Time second s
Electric current ampere A
Temperature kelvin K
Derived units combine these: force is measured in newtons, where 1 N = 1 kg·m/s2, and energy in joules, where 1 J = 1
N·m = 1 kg·m2/s2.
Dimensional Analysis
A valid equation must have the same units on both sides. Use this to check your work and to convert. To convert,
multiply by fractions equal to 1:
EX AMPLE CONVERSION
90 km/h × (1000 m / 1 km) × (1 h / 3600 s) = 25 m/s
Scalars vs. Vectors
A scalar has magnitude only (mass, time, temperature, speed, energy). A vector has magnitude and direction
(displacement, velocity, acceleration, force, momentum).
Resolve a vector of magnitude A at angle θ from the x-axis into components:
VECTOR COMPONENTS
Ax = A·cos θ Ay = A·sin θ A = √(Ax2 + Ay2) θ = tan-1(Ay/Ax)
WORKED EX AMPLE 1.1
A force of 50 N acts at 30° above the horizontal. Find its horizontal and vertical components.
© Reboot Computer Services Inc. · Created by Mario Washington · Page 2 of 14
Physics 101
The Complete Study Guide to Introductory Mechanics
Formulas · Worked Examples · Practice Problems + Solutions
Inside this guide
1 · Units, Measurement & Vectors
2 · Motion in One & Two Dimensions
3 · Newton's Laws of Motion
4 · Work, Energy & Power
5 · Momentum & Collisions
6 · Circular Motion & Gravitation
7 · Master Formula Sheet
8 · 20 Practice Problems with Full Solutions
9 · Glossary of Key Terms
A self-study companion for first-semester physics · rebootcs.com
, 1 · Units, Measurement & Vectors
Physics is a quantitative science: every claim is tied to a measurable quantity with a number and a unit. Mastering units
and vectors early prevents the majority of errors students make later.
SI Base Units
Quantity Unit Symbol
Length meter m
Mass kilogram kg
Time second s
Electric current ampere A
Temperature kelvin K
Derived units combine these: force is measured in newtons, where 1 N = 1 kg·m/s2, and energy in joules, where 1 J = 1
N·m = 1 kg·m2/s2.
Dimensional Analysis
A valid equation must have the same units on both sides. Use this to check your work and to convert. To convert,
multiply by fractions equal to 1:
EX AMPLE CONVERSION
90 km/h × (1000 m / 1 km) × (1 h / 3600 s) = 25 m/s
Scalars vs. Vectors
A scalar has magnitude only (mass, time, temperature, speed, energy). A vector has magnitude and direction
(displacement, velocity, acceleration, force, momentum).
Resolve a vector of magnitude A at angle θ from the x-axis into components:
VECTOR COMPONENTS
Ax = A·cos θ Ay = A·sin θ A = √(Ax2 + Ay2) θ = tan-1(Ay/Ax)
WORKED EX AMPLE 1.1
A force of 50 N acts at 30° above the horizontal. Find its horizontal and vertical components.
© Reboot Computer Services Inc. · Created by Mario Washington · Page 2 of 14
